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  • 1.
    Adolfsson, Lena
    et al.
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för naturvetenskapernas och matematikens didaktik.
    Benckert, Sylvia
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för fysik.
    Wiberg, Marie
    Umeå universitet, Samhällsvetenskapliga fakulteten, Statistiska institutionen.
    Gapet har minskat: skillnader mellan hög- och lågpresterande flickors och pojkars attityder till biologi, fysik och kemi 1995 och 20072011Ingår i: NorDiNa: Nordic Studies in Science Education, ISSN 1504-4556, E-ISSN 1894-1257, Vol. 7, nr 1, s. 3-16Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This article explores the change over time of boys’ and girls’ attitudes towards biology, physics and chemistry. We use data from the TIMSS studies for grade 8 in Sweden to investigate how the attitudes for high- and low performing pupils have changed between 1995 and 2007. The attitude is measured by four questions from the student questionnaire in the TIMSS study. The results indicate that there have been some changes in attitudes between 1995 and 2007. High-achieving pupils and especially boys have a more negative attitude towards all three subjects, biology, physics and chemistry, in 2007 compared to 1995. The low-achieving students think that they are performing better in all three subjects 2007 compared to 1995. The difference between the group that are most positive to physics and chemistry and the least positive group has diminished between the two years. The results are discussed in relation to the changes in Swedish schools during the period.

  • 2. Albano, Anthony D.
    et al.
    Wiberg, Marie
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Linking With External Covariates: Examining Accuracy by Anchor Type, Test Length, Ability Difference, and Sample Size2019Ingår i: Applied psychological measurement, ISSN 0146-6216, E-ISSN 1552-3497, Vol. 43, nr 8, s. 597-610Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Research has recently demonstrated the use of multiple anchor tests and external covariates to supplement or substitute for common anchor items when linking and equating with nonequivalent groups. This study examines the conditions under which external covariates improve linking and equating accuracy, with internal and external anchor tests of varying lengths and groups of differing abilities. Pseudo forms of a state science test were equated within a resampling study where sample size ranged from 1,000 to 10,000 examinees and anchor tests ranged in length from eight to 20 items, with reading and math scores included as covariates. Frequency estimation linking with an anchor test and external covariate was found to produce the most accurate results under the majority of conditions studied. Practical applications of linking with anchor tests and covariates are discussed.

  • 3.
    Andersson, Björn
    et al.
    Uppsala universitet.
    Bränberg, Kenny
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Wiberg, Marie
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    kequate: The kernel method of test equating. R package version 1.1.02012Övrigt (Övrigt vetenskapligt)
    Abstract [en]

    Implements the kernel method of test equating using the CB, EG, SG, NEAT CE/PSE and NEC designs, supporting gaussian,logistic and uniform kernels and unsmoothed and pre-smoothed input data.

  • 4.
    Andersson, Björn
    et al.
    Uppsala universitet.
    Bränberg, Kenny
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Wiberg, Marie
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Performing the Kernel Method of Test Equating with the Package kequate2013Ingår i: Journal of Statistical Software, ISSN 1548-7660, E-ISSN 1548-7660, Vol. 55, nr 6, s. 1-25Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In standardized testing it is important to equate tests in order to ensure that the test takers, regardless of the test version given, obtain a fair test. Recently, the kernel method of test equating, which is a conjoint framework of test equating, has gained popularity. The kernel method of test equating includes five steps: (1) pre-smoothing, (2) estimation of the score probabilities, (3) continuization, (4) equating, and (5) computing the standard error of equating and the standard error of equating difference. Here, an implementation has been made for six different equating designs: equivalent groups, single group, counter balanced, non-equivalent groups with anchor test using either chain equating or post- stratification equating, and non-equivalent groups using covariates. An R package for the kernel method of test equating called kequate is presented. Included in the package are also diagnostic tools aiding in the search for a proper log-linear model in the pre-smoothing step for use in conjunction with the R function glm.

  • 5.
    Andersson, Björn
    et al.
    Beijing Normal University.
    Wiberg, Marie
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Item response theory observed-score kernel equating2017Ingår i: Psychometrika, ISSN 0033-3123, E-ISSN 1860-0980, Vol. 82, nr 1, s. 48-66Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Item response theory (IRT) observed-score kernel equating is introduced for the non-equivalent groups with anchor test equating design using either chain equating or post-stratification equating. The equating function is treated in a multivariate setting and the asymptotic covariance matrices of IRT observed-score kernel equating functions are derived. Equating is conducted using the two-parameter and three-parameter logistic models with simulated data and data from a standardized achievement test. The results show that IRT observed-score kernel equating offers small standard errors and low equating bias under most settings considered.

  • 6.
    Bränberg, Kenny
    et al.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Statistiska institutionen.
    Wiberg, Marie
    Umeå universitet, Samhällsvetenskapliga fakulteten, Statistiska institutionen.
    Observed score linear equating with covariates2011Ingår i: Journal of educational measurement, ISSN 0022-0655, E-ISSN 1745-3984, Vol. 48, nr 4, s. 419-440Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper examined observed score linear equating in two different data collection designs, the equivalent groups design and the nonequivalent groups design, when information from covariates (i.e. background variables correlated with the test scores) was included. The main purpose of the study was to examine the effect (i.e. bias, variance, and mean square error) on the estimators of including this additional information. A model for observed-score linear equating with covariates first was suggested. As a second step, the model was used in a simulation study to show that the use of covariates such as gender and education can increase the accuracy of an equating by reducing the mean squared error of the estimators. Finally, data from two administrations of the Swedish Scholastic Assessment Test were used to illustrate the use of the model.

  • 7.
    Bränberg, Kenny
    et al.
    Umeå universitet, Samhällsvetenskaplig fakultet, Statistik.
    Wiberg, Marie
    Umeå universitet, Samhällsvetenskaplig fakultet, Statistik.
    The effect on equating of using background variablesManuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    In this paper observed score linear equating with two different data collection designs, the equivalent groups design and the non-equivalent groups design, is examined when including information from background variables. The purpose of the study is to examine the effect (i.e., bias, variance and mean squared error) on the estimators of including this additional information. In a simulation study, we show that the use of background variables, such as gender and education, can increase the accuracy of an equating by reducing the mean squared error (MSE) of the estimators. 

  • 8.
    Carelli, Grazia
    et al.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för psykologi.
    Wiberg, Britt
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för psykologi.
    Wiberg, Marie
    Umeå universitet, Samhällsvetenskapliga fakulteten, Statistiska institutionen.
    Development and Construct Validation of the Swedish Zimbardo Time Perspective Inventory (S-ZTPI).2011Ingår i: European Journal of Psychological Assessment, ISSN 1015-5759, E-ISSN 2151-2426, Vol. 27, nr 4, s. 220-227Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this study, we developed and evaluated a Swedish version of the Zimbardo Time Perspective Inventory (ZTPI;Zimbardo & Boyd, 1999). The original version of the ZTPI was extended by including a Future Negative scale, and the psychometric properties of both versions were examined in a sample of 419 adults aged between 18 and 80 years. Confirmatory factor analysis (CFA) provided support both for the original five-factor solution proposed byZimbardo and Boyd (1999) in a Swedish sample and for a six-factor solution with the Future Negative scale as an independent factor. These findings extend the original ZTPI and suggest that negative feelings about the future constitute a central dimension of the temporal perspective. The Swedish Zimbardo Time Perspective Inventory (S-ZTPI) provides a reliable and valid instrument for measuring time perspective in the context of Swedish research and to be beneficial in its application in multiple areas of psychology and related disciplines.

  • 9.
    Fahlén, Jessica
    et al.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Wiberg, Marie
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    KU-dag som möjlighet till erfarenhetsutbyte2016Konferensbidrag (Refereegranskat)
    Abstract [sv]

    Många lärare på högskolor och universitet har kompetensutveckling (KU) i sin tjänst vilket är reglerade i lokala avtal. Enligt Umeå universitets avtal innebär det att alla universitetslektorer ska under en treårs period ges utrymme om minst 20 procent. Vidare framgår att avrapporteringen av genomförda uppgifter ska ske på lämpligt sätt. Avstämning och revidering av lärarens kompetensutvecklingsplan sker vanligtvis på de flesta institutionerna/enheterna vid återkommande utvecklingssamtal. På vår Enhet har det vanliga varit har lärarna har genomfört sin KU utifrån sin plan och rapporterat en gång per år vid utvecklingssamtalet. Vid detta tillfälle har även planen reviderats. Tyvärr sker då inte ett erfarenhetsutbyte mellan kollegor utan enbart en avrapportering mot närmaste chef. För att förändra det här införde vi för tre år sedan på försök en KU-dag. Inspirationen till en KU-dag kom från Enhetens doktoranddag som ges en gång per år och där alla doktorander presenterar vad de har gjort det gångna året samt blickar framåt vad de ska göra det kommande året. Idén med en KU-dag är att alla som har KU-tid i sin bemanning presenterar vad de har gjort på sin tid samt en kort framåtblick på 10-15 minuter. För att engagera fler personer att delta så uppmanade vi även alla projektledare med externa medel att presentera vad de gör på sin forskningstid. Vårt huvudsakliga syfte med KU-dagen var att synliggöra vad alla gör samt att öppna upp för att lära oss av varandra men också för att öka medvetenheten om vad alla gör på Enheten. Erfarenheterna efter tre år med en årlig KU-dag har varit många. Första året så upplevde vi en viss osäkerhet bland deltagarna. Vad leder egentligen införandet av en KU-dag till? Är den till för att kontrollera ens arbete eller kan man lära sig något? Redan andra året så uttryckte flera av deltagarna att de ville delta och det pratades om det i positiva termer både inför och efter genomförandet. Detta beror troligtvis på att vi arbetat aktivt med att det inte ska kännas som en kontroll utan mer till för att dela erfarenheter. Nu efter att ha genomfört det ett tredje år så ses det som ett självklart inslag i vår verksamhet. Lärdomar vi har dragit under de här åren inkluderar betydelsen av hur man lanserar KU-dagen, när på terminen den ges för att säkerställa att så många som möjligt kan delta, samt hur värdefullt det är att vara medveten om vad andra gör för att skapa nya projekt och ett inkluderande arbetsklimat på Enheten.

  • 10. Gonzaléz, Jorge
    et al.
    Wiberg, Marie
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    The use of Poisson-Binomial distribution in equating test scores2015Konferensbidrag (Refereegranskat)
  • 11. González, Jorge
    et al.
    Wiberg, Marie
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Applying test equating methods using R2017Bok (Refereegranskat)
    Abstract [en]

    This book describes how to use test equating methods in practice. The non-commercial software R is used throughout the book to illustrate how to perform different equating methods when scores data are collected under different data collection designs, such as equivalent groups design, single group design, counterbalanced design and non equivalent groups with anchor test design. The R packages equate, kequate and SNSequate, among others, are used to practically illustrate the different methods, while simulated and real data sets illustrate how the methods are conducted with the program R. The book covers traditional equating methods including, mean and linear equating, frequency estimation equating and chain equating, as well as modern equating methods such as kernel equating, local equating and combinations of these. It also offers chapters on observed and true score item response theory equating and discusses recent developments within the equating field. More specifically it covers the issue of including covariates within the equating process, the use of different kernels and ways of selecting bandwidths in kernel equating, and the Bayesian nonparametric estimation of equating functions. It also illustrates how to evaluate equating in practice using simulation and different equating specific measures such as the standard error of equating, percent relative error, different that matters and others.

  • 12. González, Jorge
    et al.
    Wiberg, Marie
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    von Davier, Alina A.
    A note on the Poisson's binomial distribution in Item Response Theory2016Ingår i: Applied psychological measurement, ISSN 0146-6216, E-ISSN 1552-3497, Vol. 40, nr 2, s. 302-310Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Poisson's binomial (PB) is the probability distribution of the number of successes in independent but not necessarily identically distributed binary trials. The independent non-identically distributed case emerges naturally in the field of item response theory, where answers to a set of binary items are conditionally independent given the level of ability, but with different probabilities of success. In many applications, the number of successes represents the score obtained by individuals, and the compound binomial (CB) distribution has been used to obtain score probabilities. It is shown here that the PB and the CB distributions lead to equivalent probabilities. Furthermore, one of the proposed algorithms to calculate the PB probabilities coincides exactly with the well-known Lord and Wingersky (LW) algorithm for CBs. Surprisingly, we could not find any reference in the psychometric literature pointing to this equivalence. In a simulation study, different methods to calculate the PB distribution are compared with the LW algorithm. Providing an exact alternative to the traditional LWapproximation for obtaining score distributions is a contribution to the field.

    Ladda ner fulltext (pdf)
    fulltext
  • 13.
    Henriksson, Widar
    et al.
    Umeå universitet, Samhällsvetenskaplig fakultet, Beteendevetenskapliga mätningar.
    Stenlund, TovaUmeå universitet, Samhällsvetenskaplig fakultet, Beteendevetenskapliga mätningar.Sundström, AnnaUmeå universitet, Samhällsvetenskaplig fakultet, Beteendevetenskapliga mätningar.Wiberg, MarieUmeå universitet, Samhällsvetenskaplig fakultet, Beteendevetenskapliga mätningar. Umeå universitet, Samhällsvetenskaplig fakultet, Statistik.
    Proceedings from the conference: The GDE-model as a guide in driver training and testing: Umeå, May 7-8, 20072007Konferensmeddelanden, proceedings (Övrig (populärvetenskap, debatt, mm))
  • 14.
    Henriksson, Widar
    et al.
    Umeå universitet, Samhällsvetenskaplig fakultet, Beteendevetenskapliga mätningar.
    Stenlund, Tova
    Umeå universitet, Samhällsvetenskaplig fakultet, Beteendevetenskapliga mätningar.
    Sundström, Anna
    Umeå universitet, Samhällsvetenskaplig fakultet, Beteendevetenskapliga mätningar.
    Wiberg, Marie
    Umeå universitet, Samhällsvetenskaplig fakultet, Beteendevetenskapliga mätningar. Umeå universitet, Samhällsvetenskaplig fakultet, Statistik.
    The GDE-model as a guide in driver training and testing.: Proceedings from the conference, Umeå, May 7-8, 20072007Rapport (Övrigt vetenskapligt)
  • 15.
    Henriksson, Widar
    et al.
    Umeå universitet, Samhällsvetenskaplig fakultet, Beteendevetenskapliga mätningar.
    Sundström, Anna
    Umeå universitet, Samhällsvetenskaplig fakultet, Beteendevetenskapliga mätningar.
    Wiberg, Marie
    Umeå universitet, Samhällsvetenskaplig fakultet, Beteendevetenskapliga mätningar. Umeå universitet, Samhällsvetenskaplig fakultet, Statistik.
    The Swedish driving-license test: A summary of studies from the department of educational measurement2004Rapport (Övrigt vetenskapligt)
    Abstract [en]

    Since 1990, the Department of Educational Measurement at Umeå University has been commissioned to study the Swedish drivinglicense test by the Swedish National Road Administration, SNRA. Over the past few years several studies have been conducted in order to develop and improve the Swedish driving-license test. The focus of the majority of the studies has been the theory test.

    The aims of this paper were threefold: firstly to describe the development of the driver education and the driving-license test in Sweden during the past century; secondly, to summarize the findings of our research, which is related to important issues in test development; and finally, to make some suggestions for further research.

  • 16.
    Häggström, Jenny
    et al.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Wiberg, Marie
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Optimal Bandwidth Selection in Observed-Score Kernel Equating2014Ingår i: Journal of educational measurement, ISSN 0022-0655, E-ISSN 1745-3984, Vol. 51, nr 2, s. 201-211Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The selection of bandwidth in kernel equating is important because it has a direct impact on the equated test scores. The aim of this article is to examine the use of double smoothing when selecting bandwidths in kernel equating and to compare double smoothing with the commonly used penalty method. This comparison was made using both an equivalent groups design and a nonequivalent group with anchor test design. The performance of the methods was evaluated through simulation studies using both symmetric and skewed score distributions. In addition, the bandwidth selection methods were applied to real data from a college admissions test. The results show that the traditional penalty method works well although double smoothing is a viable alternative because it performs reasonably well compared to the traditional method.

    Ladda ner fulltext (pdf)
    fulltext
  • 17. L. van der Ark, Andries
    et al.
    Wiberg, MarieUmeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.Culpepper, Steven A.Douglas, Jeffrey A.Wang, Wen-Chung
    Quantitative psychology. The 81st annual meeting of the Psychometric society, Asheville, North Carolina, 20162017Proceedings (redaktörskap) (Refereegranskat)
  • 18.
    Laukaityte, Inga
    et al.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Wiberg, Marie
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Importance of sampling weights in multilevel modeling of international large-scale assessment data2018Ingår i: Communications in Statistics - Theory and Methods, ISSN 0361-0926, E-ISSN 1532-415X, Vol. 47, nr 20, s. 4991-5012Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Multilevel modeling is an important tool for analyzing large-scale assessment data. However, the standard multilevel modeling will typically give biased results for such complex survey data. This bias can be eliminated by introducing design weights which must be used carefully as they can affect the results. The aim of this paper is to examine different approaches and to give recommendations concerning handling design weights in multilevel models when analyzing large-scale assessments such as TIMSS (The Trends in International Mathematics and Science Study). To achieve the goal of the paper, we examined real data from two countries and included a simulation study. The analyses in the empirical study showed that using no weights or only level 1 weights sometimes could lead to misleading conclusions. The simulation study only showed small differences in estimation of the weighted and unweighted models when informative design weights were used. The use of unscaled or not rescaled weights however caused significant differences in some parameter estimates.

  • 19.
    Laukaityte, Inga
    et al.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Wiberg, Marie
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Using plausible values in secondary analysis in large–scale assessments2017Ingår i: Communications in Statistics - Theory and Methods, ISSN 0361-0926, E-ISSN 1532-415X, Vol. 46, nr 22, s. 11341-11357Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Plausible values are typically used in large–scale assessment studies, in particular in the Trends in International Mathematics and Science Study and the Programme for International Student Assessment. Despite its large spread there are still some questions regarding the use of plausible values and how such use affects statistical analyses. The aim of this paper is to demonstrate the role of plausible values in large–scale assessment surveys when multilevel modelling is used. Different user strategies concerning plausible values for multilevel models as well as means and variances are examined. The results show that some commonly used user strategies give incorrect results while others give reasonable estimates but incorrect standard errors. These findings are important for anyone wishing to make secondary analyses of large–scale assessment data, especially those interested in using multilevel models to analyze the data.

  • 20. Leôncio, Waldir
    et al.
    Wiberg, Marie
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Evaluating equating transformations from different frameworks2018Ingår i: Quantitative psychology: the 82nd annual meeting of the Psychometric Society, Zurich, Switzerland, 2017 / [ed] Marie Wiberg, Steven Culpepper, Rianne Janssen, Jorge González, Dylan Molenaar, Cham, Switzerland: Springer, 2018, s. 101-110Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    Test equating is used to ensure that test scores from different test forms can be used interchangeably. This paper aims to compare the statistical and computational properties from three equating frameworks: item response theory observed-score equating (IRTOSE), kernel equating and kernel IRTOSE. The real data applications suggest that IRT-based frameworks tend to providemore stable and accurate results than kernel equating. Nonetheless, kernel equating can provide satisfactory results if we can find a good model for the data, while also being much faster than the IRT-based frameworks. Our general recommendation is to try all methods and examine how much the equated scores change, always ensuring that the assumptions are met and that a good model for the data can be found.

  • 21. Li, Juan
    et al.
    Ramsay, James O.
    Wiberg, Marie
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    TestGardener: a program for optimal scoring and graphical analysis2019Ingår i: Quantitative psychology: 83rd annual meeting of the psychometric society, New York, NY 2018 / [ed] Marie Wiberg, Steven Culpepper, Rianne Janssen, Jorge González, Dylan Molenaar, D., New York: Springer, 2019, s. 87-94Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    The aim of this paper is to demonstrate how to use TestGardener to analyze testing data with various item types and explain some main displays. TestGardener is a software designed to aid the development, evaluation, and use of multiple choice examinations, psychological scales, questionnaires, and similar types of data. This software implements the optimal scoring of binary and multi-option items, and uses spline smoothing to obtain item characteristics curves (ICCs) that better fit the real data. Using TestGardner does not require any programming skill or formal statistical knowledge, which will make optimal scoring and item response theory more approachable for test analysts, test developers, researchers, and general public.

  • 22. Lindvall, Jannika
    et al.
    Helenius, Ola
    Wiberg, Marie
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Critical features of professional development programs: Comparing content focus and impact of two large-scale programs2018Ingår i: Teaching and Teacher Education: An International Journal of Research and Studies, ISSN 0742-051X, E-ISSN 1879-2480, Vol. 70, s. 121-131Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    By comparing two large-scale professional development programs' content and impact on student achievement, we contribute to research on critical features of high quality professional development, especially content focus. Even though the programs are conducted in the same context and are highly similar if characterized according to established research frameworks, our results suggest that they differ in their impact on student achievement. We therefore develop an analytical framework that allow us to characterize the programs' content and delivery in detail. Through this approach, we identify important differences between the programs that provide explanatory value in discussing reasons for their differing impacts.

  • 23.
    Pettersson, Lennart
    et al.
    Umeå universitet, Humanistiska fakulteten, Konstvetenskap.
    Wiberg, Marie
    Umeå universitet, Samhällsvetenskapliga fakulteten, Statistiska institutionen.
    Sålt och lottat: en studie av privatinköp och lotterier i Norrlands konstförening 1883 och 18842006Rapport (Övrigt vetenskapligt)
  • 24.
    Pettersson, Lennart
    et al.
    Umeå universitet, Humanistiska fakulteten, Konstvetenskap.
    Wiberg, Marie
    Umeå universitet, Samhällsvetenskapliga fakulteten, Statistiska institutionen.
    Sålt och lottat: en studie av privatinköp och lotterier i Norrlands konstförening 1883 och 18842005Bok (Övrigt vetenskapligt)
  • 25. Ramsay, James
    et al.
    Li, Juan
    Wiberg, Marie
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Workshop: Learning More from Test Data: New Tools for Test Scoring2019Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    The aim of scoring a test is to give as best estimate of an examinee’s ability as possible. The goals of this training session are for the attendees to be able to understand and implement optimal test scoring, and to interpret the results of optimal scoring in a reasonable way. In this training session, we will demonstrate and guide the attendees to use the web-based software TestGardener to implement optimal test scoring on real educational test data. Most of the outputs of this software are in graphical form, and the software is used interactively. The main part of the training session is devoted to practical exercises in how to analyze test data. Optimal scoring will also be compared with the traditional sum scoring, and recent developments in test scoring will be discussed. Expected audience include researchers, graduate students and practitioners. An introductory statistical background is recommended but not required. Please note, programming knowledge is not required.

  • 26. Ramsay, James O.
    et al.
    Wiberg, Marie
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    A Strategy for Replacing Sum Scoring2017Ingår i: Journal of educational and behavioral statistics, ISSN 1076-9986, E-ISSN 1935-1054, Vol. 42, nr 3, s. 282-307Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This article promotes the use of modern test theory in testing situations where sum scores for binary responses are now used. It directly compares the efficiencies and biases of classical and modern test analyses and finds an improvement in the root mean squared error of ability estimates of about 5% for two designed multiple-choice tests and about 12% for a classroom test. A new parametric density function for ability estimates, the tilted scaled , is used to resolve the nonidentifiability of the univariate test theory model. Item characteristic curves (ICCs) are represented as basis function expansions of their log-odds transforms. A parameter cascading method along with roughness penalties is used to estimate the corresponding log odds of the ICCs and is demonstrated to be sufficiently computationally efficient that it can support the analysis of large data sets.

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  • 27. Ramsay, James O.
    et al.
    Wiberg, Marie
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Breaking through the sum scoring barrier2017Ingår i: Quantitative Psychology: The 81st annual meeting of the psychometric society, Asheville, North Carolina, 2016 / [ed] L. Andries van der Ark, Marie Wiberg, Steven A. Culpepper, Jeffrey A. Douglas, Wen-Chung Wang, Cham: Springer, 2017, s. 151-158Konferensbidrag (Refereegranskat)
    Abstract [en]

    The aim of this paper is to reflect around what would be needed in order to replace sum scoring, including technical advances, communivation with both test constructors and examinees, and organizational strategy. Sum scoring are proposed to be replaces by smart scoring and a brief description, and some theoretical support for smart scoring and methods for achieving it are given together with an example from a large-scale assessment test.

  • 28. Ramsay, James
    et al.
    Wiberg, Marie
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Li, Juan
    Full Information Optimal Scoring2019Ingår i: Journal of educational and behavioral statistics, ISSN 1076-9986, E-ISSN 1935-1054Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Ramsay and Wiberg used a new version of item response theory that represents test performance over nonnegative closed intervals such as [0, 100] or [0, n] and demonstrated that optimal scoring of binary test data yielded substantial improvements in point-wise root-mean-squared error and bias over number right or sum scoring. We extend these results by showing that optimal scoring of the full information in option choices produces about as much further improvement in these measures of score performance as was achieved by going from sum scoring to optimal binary scoring.

  • 29.
    Rolfsman, Ewa
    et al.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för tillämpad utbildningsvetenskap.
    Wiberg, Marie
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Laukaityte, Inga
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    School effectiveness in the Nordic countries in relation to PISA and TIMSS2013Konferensbidrag (Refereegranskat)
    Abstract [en]

    In a Nordic perspective, the finish students overall achieve the highest score on PISA (Programme for International Student Assessment), while the Swedish students exhibit declining results. The results of the Swedish students have drawn attention to the quality of education and the role of the educational professionals and the efficiency of the school. It is therefore of vital importance to investigate whether these results can be related to school level factors in a Nordic perspective. However, TIMSS (Trends in International Mathematics and Science Study) and PISA exhibit similarities as well as differences as they target different subjects. In addition, the results on TIMSS and PISA differ between countries. The aim of this study is to investigate whether school level factors can contribute to the explanation of the results for the Nordic countries participating in PISA 2009 and, if so, identify factors that can be influenced in order to enhance students’ achievement. We focus on school effectiveness in relation to PISA, since all Nordic countries participate in PISA. However, the results are contrasted to results from TIMSS for Sweden and Norway. In order to separate the effect of school level variables from the effect of student’s home environment and to take care of the sampling design used in TIMSS and PISA, multilevel analysis was used. The results show that only a few school level factors were significant, and only in Sweden and Finland. Furthermore, school level factors in Sweden and Norway on PISA differ from school level factors based on TIMSS data.

  • 30. Sansivieri, Valentina
    et al.
    Wiberg, Marie
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    IRT observed-score equating with the non-equivalent groups with covariates design2017Ingår i: Quantitative Psychology: The 81st Annual Meeting of the Psychometric Society, Asheville, North Carolina, 2016 / [ed] L. Andries van der Ark, Marie Wiberg, Steven A. Culpepper, Jeffrey A. Douglas, Wen-Chung Wang, Cham: Springer, 2017, s. 275-285Konferensbidrag (Refereegranskat)
    Abstract [en]

    Nonequivalent groups with anchor test (NEAT) design is typically preferred in test score equating, but there are tests which do not administer an anchor test. If the groups are nonequivalent, an equivalent groups (EG) design cannot be recommended. Instead, one can use a nonequivalent groups with covariates (NEC) design. The overall aim of this work was to propose the use of item response theory (IRT) with a NEC design by incorporating the mixed-measurement IRT with covariates model within IRT observed-score equating in order to model both test scores and covariates. Both simulations and a real test example are used to examine the proposed test equating method in comparison with traditional IRT observed-score equating methods with an EG design and a NEAT design. The results show that the proposed method can be used in practice, and the simulations show that the standard errors of the equating are lower with the proposed method as compared with traditional methods.

  • 31. Sansivieri, Valentina
    et al.
    Wiberg, Marie
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Linking Scales in Item Response Theory with Covariates2018Ingår i: Journal of Research in Education, Science and Technology, ISSN 2548-0286, Vol. 3, nr 2, s. 12-32Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    When test forms are administered to different non-equivalent groups of examinees and are scored by item response theory (IRT), it is necessary to put item parameters estimated separately on two groups on the same scale. In the IRT models which include covariates about the examinees, we have two parameters which model uniform and non-uniform differential item functioning (DIF) and that have to be put on the same scale. The aim of this study is to propose conversion equations, which are used to put the uniform and non-uniform DIF parameters on the same scale. To estimate the coefficients of the conversion equations we will use four methods: mean/mean, mean/sigma, Haebara and Stocking-Lord. We give a simulation study and an empirical example. The results of the simulation study show that the coefficients of the conversion equations are substantially equal for the Haebara and Stocking-Lord methods, while they are different for the other methods. The results of the empirical example is that IRT with covariates produces a more informative test than using IRT without covariates for high abilities’ values and, when the mean-mean and the mean-sigma methods are used, we obtain more informative tests than when using concurrent calibration.

  • 32. Sansivieri, Valentina
    et al.
    Wiberg, Marie
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Matteucci, Mariagiulia
    A review of test equating methods with a special focus on IRT-based approaches2017Ingår i: Statistica, ISSN 1973-2201, Vol. 77, nr 4, s. 329-352Artikel, forskningsöversikt (Refereegranskat)
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  • 33.
    Sundström, Anna
    et al.
    Umeå universitet, Samhällsvetenskaplig fakultet, Beteendevetenskapliga mätningar.
    Henriksson, Widar
    Umeå universitet, Samhällsvetenskaplig fakultet, Beteendevetenskapliga mätningar.
    Wiberg, Marie
    Umeå universitet, Samhällsvetenskaplig fakultet, Beteendevetenskapliga mätningar. Umeå universitet, Samhällsvetenskaplig fakultet, Statistik.
    Alger, Susanne
    Umeå universitet, Samhällsvetenskaplig fakultet, Beteendevetenskapliga mätningar.
    "Ett givet inslag i förarutbildningen": Umeå universitet försvarar självvärderingen2008Ingår i: Mitt i trafiken, nr 1, s. 33-33Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
    Abstract [en]

    Sammanfattningsvis framstår det som en självklarhet att självvärdering ska vara ett inslag i såväl förarutbildning som förar­prov eftersom det utgör en väsentlig del i den nya kursplanen. Det står också klart att många vinster, både för lärandet och tra­fiksäkerheten, kan göras genom att införa självvärdering i utbildningen. Nästa steg är att diskutera hur detta ska genomföras i praktiken genom att finna sätt för hur självvärdering ska användas både i utbild­ning och i förarprov.

  • 34.
    Sundström, Anna
    et al.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Beteendevetenskapliga mätningar.
    Wiberg, Marie
    Umeå universitet, Samhällsvetenskapliga fakulteten, Statistiska institutionen. Umeå universitet, Samhällsvetenskapliga fakulteten, Beteendevetenskapliga mätningar.
    Den svenska förarprövningens resultat: sambandet mellan kunskapsprovet och körprovet för underkända och godkända provtagare2005Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    The Swedish driving-license test consists of a theory test and a practical test. The purpose of these tests is to investigate if the learner driver has the knowledge and abilities stated in the curriculum. The purpose of this study was threefold. Firstly, the purpose was to examine the relationship between the theory test and the practical test in a sample where testtakers that both passed and failed the theory test is included. Secondly, the purpose was to study the structure of the test score and the performance of the test-takers with regard to age, gender and driver education. Thirdly, the purpose was to investigate the relationship between self-assessed performance and test performance.

    The results on the theory test were similar compared to previous studies which indicated that the sample used was representative for the population of test-takers. However, many test-takers repeat the test several times and the percentage of test-takers taking the test for the first time has decreased. The results on the practical test in this study showed that pass rates have decreased compared to previous studies. One possible explanation for this is that the pass-rates are affected by the fact that test-takers who failed the theory test are included in the sample, and thus the test-takers limited theoretical knowledge is reflected in the decrease in pass-rates. When the relationship between the tests was examined the results indicated that the correlation was stronger than in previous studies. Moreover, the results showed that students from traffic school performed better on the theory test compared to private learners. The results on the practical test showed that students from traffic school, and those who combined professional education with private driver training, performed better than private learners. With regard to self-assessed performance, results indicated a relationship between performance on the theory test and self-evaluation. Testtakers performing high on the test rated their performance high and vice versa.

    The main conclusions of the study was that there is a relationship between theory and practice, in that sense that those performing well on the theory test perform better on the practical test compared to those performing less well on the theory test. Moreover, students from traffic school perform better on both the theory test and the practical test compared to private learners.

  • 35. van der Ark, Andries
    et al.
    Bolt, Daniel MWang, Wen-ChungDouglas, Jeffrey A.Wiberg, MarieUmeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Quantitative Psychology Research: The 80th Annual Meeting of the Psychometric Society, Beijing, 20152016Proceedings (redaktörskap) (Refereegranskat)
  • 36.
    van der Linden, Wim J.
    et al.
    CTB/McGraw-Hill, Monterey, California.
    Wiberg, Marie
    Umeå universitet, Samhällsvetenskapliga fakulteten, Statistiska institutionen.
    Local observed-score equating with anchor-test designs2010Ingår i: Applied psychological measurement, ISSN 0146-6216, E-ISSN 1552-3497, Vol. 34, nr 8, s. 620-640Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    For traditional methods of observed-score equating with anchor-test designs, such as chain and poststratification equating, it is difficult to satisfy the criteria of equity and population invariance. Their equatings are therefore likely to be biased. The bias in these methods was evaluated against a simple local equating method in which the anchor-test score was used as a proxy of the proficiency measured by the test and the equating was conditional on this score. The results showed substantial bias for the two traditional methods under a variety of conditions but much smaller bias for the local method. In addition, unlike the traditional methods, the local method appeared to be quite robust with respect to changes in the difficulty and accuracy of the two tests that were equated. But like these methods, it appeared to be sensitive to a decrease in the accuracy of the anchor test as a proxy of the ability measured by the tests.

  • 37.
    Wallin, Gabriel
    et al.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Häggström, Jenny
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Wiberg, Marie
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    How Important is the Choice of Bandwidth in Kernel Equating?Manuskript (preprint) (Övrigt vetenskapligt)
  • 38.
    Wallin, Gabriel
    et al.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Häggström, Jenny
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Wiberg, Marie
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    How to select the bandwidth in kernel equating: an evaluation of five different methods2018Ingår i: Quantitative psychology: the 82nd annual meeting of the Psychometric Society, Zurich, Switzerland, 2017 / [ed] Marie Wiberg, Steven Culpepper, Rianne Janssen, Jorge González, Dylan Molenaar, Cham, Switzerland: Springer, 2018, s. 91-100Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    When using kernel equating to equate two test forms, a bandwidth needs to be selected. The bandwidth parameter determines the smoothness of the continuized score distributions and has been shown to have a large effect on the kernel density estimate. There are a number of suggested criteria for selecting the bandwidth, and currently four of them have been implemented in kernel equating. In this paper, all four of the existing bandwidth selectors suggested for kernel equating are evaluated and compared against each other using real test data together with a new criterion that implements leave-one-out cross-validation. Although the bandwidth methods generally were similar in terms of equated scores, there were potentially important differences in the upper part of the score scale where critical admission decisions are typically made.

  • 39.
    Wallin, Gabriel
    et al.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Wiberg, Marie
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Kernel Equating Using Propensity Scores for Nonequivalent Groups2019Ingår i: Journal of educational and behavioral statistics, ISSN 1076-9986, E-ISSN 1935-1054, Vol. 44, nr 4, s. 390-414Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    When equating two test forms, the equated scores will be biased if the test groups differ in ability. To adjust for the ability imbalance between nonequivalent groups, a set of common items is often used. When no common items are available, it has been suggested to use covariates correlated with the test scores instead. In this article, we reduce the covariates to a propensity score and equate the test forms with respect to this score. The propensity score is incorporated within the kernel equating framework using poststratification and chained equating. The methods are evaluated using real college admissions test data and through a simulation study. The results show that propensity scores give an increased equating precision in comparison with the equivalent groups design and a smaller mean squared error than by using the covariates directly. Practical implications are also discussed.

  • 40.
    Wallin, Gabriel
    et al.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Wiberg, Marie
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Model Selection for Presmoothing of Bivariate Score Distributions in Kernel EquatingManuskript (preprint) (Övrigt vetenskapligt)
  • 41.
    Wallin, Gabriel
    et al.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Wiberg, Marie
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Nonequivalent groups with covariates design using propensity scores for kernel equating2017Ingår i: Quantitative Psychology: The 81st Annual Meeting of the Psychometric Society, Asheville, North Carolina, 2016 / [ed] van der Ark L., Wiberg M., Culpepper S., Douglas J., Wang WC., Cham: Springer, 2017, s. 309-319Konferensbidrag (Refereegranskat)
    Abstract [en]

    In test score equating, the non-equivalent groups with covariates (NEC) design uses covariates with high correlation to the test scores as a substitute for an anchor test when the latter is lacking. However, as the number of covariates increases, the number of observations for each covariate combination decreases. We suggest to use propensity scores instead, which we include in the kernel equating framework using both post-stratification and chained equating. The two approaches are illustrated with data from a large scale assessment, and the results show an increased precision in comparison with the equivalent groups design, and great similarities in comparison with the results when using an anchor test.

  • 42.
    Wiberg, Britt
    et al.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för psykologi.
    Sircova, Anna
    DIS Copenhagen.
    Wiberg, Marie
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Carelli, Maria Grazia
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för psykologi.
    Balanced time perspective: developing empirical profile and exploring its stability over time2017Ingår i: Time perspective: theory and practice / [ed] Aleksandra Kostić, Derek Chadee, London: Palgrave Macmillan, 2017, s. 63-95Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    Balanced time perspective (BTP) is characterized by flexible switching between a person's past, present and future time orientations, depending on situational demands, personal resources, experiences, and social evaluations. The present study aimed to explore the psychological characteristics of people with a BTP profile and attain a deeper understanding of the BTP construct. Seven people with BTP profiles were investigated using in-depth interviews, self-report instruments, and a projective test. By testing the participants on two occasions within an 18-month interval, we investigated the stability of BTP. Analyses showed that participants were aware of the "now" and had a synchronicity between the present and the past, and also between the present and the future. Results indicated a degree of temporal stability in the BTP profile and that people's interpretations and interactions within the surrounding context of events influences their time perspectives.

  • 43.
    Wiberg, Britt
    et al.
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för psykologi.
    Wiberg, Marie
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Carelli, Maria Grazia
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för psykologi.
    Sircova, Anna
    Umeå universitet, Samhällsvetenskapliga fakulteten, Institutionen för psykologi.
    A qualitative and quantitative study of seven persons with balanced time perspective (BTP) according to S-ZTPI2012Ingår i: 1st international conference on time perspective and research: converging paths in psychology time theory and research / [ed] Maria Paula Paixao, Victor E.C. Ortuno, Pedro Cordeiro, Rute David, ESPACOBRANCO , 2012, s. 120-120Konferensbidrag (Refereegranskat)
    Abstract [en]

    The theoretical notion of balanced time perspective (BTP) has been suggested by a number of authors and some attempts to operationalize BTP (Boniwell, 2005; Drake, Duncan, Sutherland, Abernethy & Henry, 2008; Sircova & Mitina, 2008; Boniwell, Osin, Linley & Ivanchenko, 2010) has been done. The aim of the present study was to get a deeper understanding of the BTP-concept by studying seven BTP-persons with both interviews and self-rating scales (e.g. SCL-90, Life Events scale, Scales of Psychological Well-Being (C. Ryff) and Satisfaction with Life Scale (E.Diener) at two occasions. Swedish Zimbardo Time Perspective Inventory (S-ZTPI) (Carelli, Wiberg & Wiberg, 2011) was administered in order to study the stability and change in BTP-level. The results showed a great stability in the BTP-level (Wiberg, Sircova, Wiberg& Carelli, in press), although a small change was observed. The 14 interviews were analyzed according to Interpretative Phenomenological Analysis (IPA). The result shows a consciousness about the "now" among the participants and a synchronicity between the present and the past and also between the present and the future. The results give strength to a holistic present scale (Zimbardo & Boyd, 2008) and an "extended now".

  • 44.
    Wiberg, Marie
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    A note on equating test scores with covariates2015Ingår i: Festschrift in honor of Hans Nyquist on the occasion of his 65th birthday / [ed] Ellinor Fackle-Fornius, Stockholm: Stockholm University, 2015, s. 96-99Kapitel i bok, del av antologi (Refereegranskat)
  • 45.
    Wiberg, Marie
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Alternative linear item response theory observed-score equating methods2016Ingår i: Applied psychological measurement, ISSN 0146-6216, E-ISSN 1552-3497, Vol. 40, nr 3, s. 180-199Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Item response theory observed-score equating (IRTOSE) is widely used in many testing programs. The aim of this study was to empirically examine three alternative linear IRTOSE methods compared with the traditional IRTOSE method and to discuss these methods in light of previously suggested alternatives. This contribution is both conceptual, by exploring three alternative methods that fit into the current observed-score equating framework, and empirical by comparing the methods through simulations and with real data. The results show that the local linear (kernel) IRTOSE methods yield low bias and low values on loss measures. However, using only a linear IRTOSE method results in excessive bias and cannot be recommended because of the ease with which IRTOSE with full distributions can be performed. An example using real data showed considerable differences in the equated scores with the alternative methods as well as in comparison with the traditional IRTOSE method. Practical considerations are given in the concluding remarks.

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  • 46.
    Wiberg, Marie
    Umeå universitet, Samhällsvetenskapliga fakulteten, Statistiska institutionen. Umeå universitet, Samhällsvetenskapliga fakulteten, Beteendevetenskapliga mätningar.
    An optimal design approach to criterion-referenced computerized testing2003Ingår i: Journal of educational and behavioral statistics, ISSN 1076-9986, E-ISSN 1935-1054, Vol. 28, nr 2, s. 97-110Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A criterion-referenced computerized test is expressed as a statistical hypothesis problem. This admits that it can be studied by using the theory of optimal design. The power function of the statistical test is used as a criterion function when designing the test. A formal proof is provided showing that all items should have the same item characteristics, i.e. items that have high discrimination, low guessing and difficulty near the cut-off score give the most powerful statistical test. An efficiency study shows how many times more items are needed if nonoptimal items are used instead of optimal items in order to get the same power in the test.

  • 47.
    Wiberg, Marie
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Analys och modellering av svenska elevers prestationer i TIMSS och PISA i ett internationellt perspektiv2015Rapport (Övrigt vetenskapligt)
  • 48.
    Wiberg, Marie
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Book review of Alina A. von Davier (Ed.) (2011) Statistical Models for Test Equating, Scaling, and Linking2013Ingår i: Psychometrika, ISSN 0033-3123, E-ISSN 1860-0980, Vol. 78, nr 1, s. 185-187Artikel, recension (Refereegranskat)
  • 49.
    Wiberg, Marie
    Umeå universitet, Samhällsvetenskapliga fakulteten, Handelshögskolan vid Umeå universitet, Statistik.
    Can a multidimensional test be evaluated with unidimensional item response theory?2012Ingår i: Educational Research and Evaluation, ISSN 1380-3611, E-ISSN 1744-4187, Vol. 18, nr 4, s. 307-320Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The aim of this study was to evaluate possible consequences of using unidimensional item response theory (UIRT) on a multidimensional college admission test. The test consists of 5 subscales and can be divided into two sections, that is, it can be considered both as a unidimensional and a multidimensional test. The test was examined with both UIRT and multidimensional IRT (MIRT). Simulations were used to examine item and ability parameter recovery when UIRT and MIRT models were used. The results obtained from the college admission test showed that although we get a better model fit when using MIRT instead of UIRT, the difference is small if we compare it with using a consecutive UIRT approach. The results from the simulations indicate that if the test only has between-item multidimensionality, it is probably not harmful to use UIRT instead of MIRT models.

  • 50.
    Wiberg, Marie
    Umeå universitet, Samhällsvetenskaplig fakultet, Beteendevetenskapliga mätningar. Statistik.
    Changes in the Swedish driving-license test?: Using the GDE framework2007Ingår i: Proceedings from the conference: The GDE-model as a guide in driver training and testing: Umeå, May 7-8, 2007, 2007Konferensbidrag (Övrigt vetenskapligt)
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