umu.sePublications
Change search
Refine search result
1234567 151 - 200 of 303
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 151.
    Häggström Lundevaller, Erling
    Umeå University, Faculty of Social Sciences, Statistics.
    Test of random subject effects in heteroskedastic linear models2001In: Statistical Sociaty of Canada. Simon Fraser University, British Clumbia.: The Joint Meetings of the Statistical Society of Canada, 2001Conference paper (Other (popular science, discussion, etc.))
  • 152.
    Häggström Lundevaller, Erling
    Umeå University, Faculty of Social Sciences, Department of Statistics.
    Tests of random effects in linear and non-linear models2002Doctoral thesis, monograph (Other academic)
  • 153.
    Häggström Lundevaller, Erling
    Umeå University, Faculty of Social Sciences, Department of Statistics. Umeå University, Faculty of Social Sciences, Centre for Population Studies (CPS).
    The effect of travel cost on frequencies of shopping and recreational trips in Sweden2009In: Journal of Transport Geography, ISSN 0966-6923, E-ISSN 1873-1236, Vol. 17, no 3, p. 208-215Article in journal (Refereed)
    Abstract [en]

    This article focus on how the cost of travel affects travel behavior. A trip frequency model for recreational and shopping trips is suggested and used to investigate this. The data that is used comes from a Swedish travel habit survey where the respondents’ trip frequencies of both types of trips on a certain day are recorded. This is likely to introduce a correlation structure, which is incorporated in the model. Special attention is paid to the effect of travel cost on trip frequencies for different regions and income groups. As a measure of the sensitivity of cost changes, elasticity of demand is calculated. The precision of the elasticities are evaluated with simulated p-values.

  • 154.
    Häggström Lundevaller, Erling
    et al.
    Umeå University, Faculty of Social Sciences, Department of Statistics. Umeå University, Faculty of Social Sciences, Centre for Population Studies (CPS).
    Edvinsson, Sören
    Umeå University, Faculty of Social Sciences, Centre for Population Studies (CPS). Umeå University, Faculty of Social Sciences, Demographic Data Base.
    The effect of the Rh negative disease on perinatal mortality: Evidence from Skellefteå 1840-19002010Conference paper (Other academic)
    Abstract [en]

    Background: The Rh-negative gene is a well known cause of perinatalmortality especially before there were any effective treatment. The Rh disease, that is caused by a Rh positive foetus carried by a Rh negativemother, leads to typical patterns of perinatal mortality with an increaseof mortality with parity and mortality clustered in families. This effecthas been largely neglected in earlier papers trying to explain mortalitypatterns in historic data.

    Objectives: This paper highlights the role of this gene in causing these patterns and tries to quantify the effect in a society with a large group of Rh-negative persons and no access to treatment.

    Methods: The risks of the Rh disease is approximately known from the medical literature. Knowing family sizes and the approximate share of Rh negative genes the ”theoretical” patterns of perinatal mortality can becalculated and simulated. Comparing these figures with observed patterns of perinatal deaths the relative importance of Rh factor can be estimated.We have used data from 1840-1900 in the Swedish parish of Skellefteå where we have data on all births and their outcomes as well as good estimates of the Rh negative gene frequency.

    Results: The results show that the Rh gene is likely to have had an important role in perinatal mortality and the patterns with more dead at high parities and clustering explaining a relatively large part of these phenomenon in high Rh negative gene societies.

    Conclusions: The paper shows that the Rh-disease is an important fac-tor in understanding mortality patterns. Its great effect on the patterns makes it necessary to take it into account when analysing other factors that can affect perinatal mortality patterns.

  • 155.
    Häggström Lundevaller, Erling
    et al.
    Umeå University, Faculty of Social Sciences, Statistics. Social and Economic Geography.
    Holm, Einar
    Social and Economic Geography.
    Strömgren, Magnus
    Social and Economic Geography.
    Lindgren, Urban
    Social and Economic Geography.
    Spatial dynamic micro-simulation of demographic development2007In: 1st General Conference of the International Microsimulation Association: Celebrating 50 Years of Microsimulation, 2007Conference paper (Other academic)
    Abstract [en]

    In a world of changing demographical patterns, tools for keeping track of these changes are of great importance. Different regions are in different stages of the demographic transition and are affected differently of migration patterns. A tool to project the demographic development at a regional level is therefore of great importance. This article we discusses the demographic development in the county Västerbotten in Sweden and in that context why and how a micro simulation model can be used for these purposes.

  • 156.
    Häggström Lundevaller, Erling
    et al.
    Umeå University, Faculty of Social Sciences, Statistics.
    Laitila, Thomas
    Umeå University, Faculty of Social Sciences, Statistics.
    Test of random subject effects in heteroskedastic linear models2002In: Biometrical Journal, ISSN 0323-3847, Vol. 44, no 7Article in journal (Refereed)
  • 157.
    Häggström Lundevaller, Erling
    et al.
    Umeå University, Faculty of Social Sciences, Department of Statistics.
    Lindgren, Urban
    Umeå University, Faculty of Social Sciences, Department of Social and Economic Geography.
    Strömgren, Magnus
    Umeå University, Faculty of Social Sciences, Department of Social and Economic Geography.
    Statistik i geografi: Slutrapport av pedagogiskt projekt2010Report (Other academic)
    Abstract [sv]

    Statistik ingår som ett viktigt hjälpämne i andra akademiska ämnen som använder kvantitativa data, till exempel kulturgeografi. Kulturgeografi har vidare betydande inslag av användning av Geografiska informationssystem (GIS), där det finns stora beröringsytor med statistik. En integrering av områdena geografi och statistik kan således ge studenterna stort mervärde. Det innebär ofta en pedagogisk utmaning att förmedla statistisk kunskap till studenter som i huvudsak har sin bakgrund inom ämnen som innehåller lite kontakt med statistiska tankegångar. Detta projekts huvudsyfte har varit att utveckla en pedagogisk ansats som är lämplig i denna situation. Projektet har i första hand genomförts inom ramen för en kurs på avancerad nivå, där statistik och geografi integrerats och lärts ut med en casebaserad ansats.

  • 158.
    Häggström Lundevaller, Erling
    et al.
    Umeå University, Faculty of Social Sciences, Department of Statistics. Umeå University, Faculty of Social Sciences, Centre for Population Studies (CPS).
    Sander, Nikola
    Skirbekk, Vegard
    Samir, K.C.
    Prospects for later-life migration in urban Europe2010Report (Other academic)
    Abstract [en]

    Objectives/Aims:Later life migration among the baby boomer generation will have far-reachingimplications of economic development and for planning strategies to ensure adequatehealth, housing and welfare in the right place at the right time. However, much of thecurrent debate about the future trajectory of this type of human mobility has been basedon speculation. The goal of this research is to gain a better understanding of later lifemigration and the likely future trajectory of the retired baby boomers in Europe.The need for more accurate forecasts of future migration flows has increased withthe relative importance of migration vis-à-vis other components of population dynamics.Although forced international migration has been given considerable research attentionin recent years, also other migration types, in particular later-life migration, becomeincreasingly important. In the coming decade, the large baby boom generation will reachretirement age.Methodology/ Results / Findings / Conclusion:The objective of this report is to focus on the effects of an ageing population interms of urban development and retirement migration. The report discusses the regionalpopulation projections and its social impacts. An analysis on the impacts of urbanizationand differential ageing across regions will be given.Moving beyond the simple assumption of a continuation of current trends, anumber of alternative scenarios are explored to simulate the likely future trajectories ofthe baby boomers. Potential impacts on retirement migration caused by changes inaverage retirement age, altered lifestyle preferences and the large size of the baby boomergeneration are considered.

  • 159.
    Häggström Lundevaller, Erling
    et al.
    Umeå University, Faculty of Social Sciences, Department of Statistics. Umeå University, Faculty of Social Sciences, Department of Social and Economic Geography.
    Terämä, Emma
    Demographic projections at local level for case study regions: Report for Peri-urban land use relationships (PLUREL), Module 1, EU sixth framework programme2008Report (Other academic)
  • 160.
    Håglin, Lena
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Family Medicine.
    Bäckman, Lennart
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Family Medicine.
    Törnkvist, Birgitta
    Umeå University, Faculty of Social Sciences, Department of Statistics.
    A structural equation model for assessment of links between changes in serum triglycerides, -urate, and -glucose and changes in serum Calcium, -magnesium and -phosphate in Type 2 diabetes and non-diabetes metabolism2011In: Cardiovascular Diabetology, ISSN 1475-2840, E-ISSN 1475-2840, Vol. 10, no 1, p. 116-Article in journal (Refereed)
    Abstract [en]

    Background: This study investigates the associations between changes in serum Triglycerides (S-TG), -Urate (S-Urate), and -Glucose (S-Glu) and changes in serum Calcium (S-Ca), -Magnesium (S-Mg), and -Phosphate (S-P) in patients with type 2 diabetes compared with non-diabetic patients. Methods: The analysis is based on data collected from a secondary prevention population of women and men (W/M) at risk for cardiovascular disease (type 2 diabetes, 212/200; non-diabetes 968/703). The whole population (n = 2083) had a mean age of 51.0 (9.7) years and was stratified for sex and according to type 2 diabetes or non-diabetes. The patients were followed for, either half a year or one year and changes in risk factors were calculated from follow-up to baseline, the time when patients were admitted to the health center. The pattern of relationships was evaluated using a structural equation model. Results: Higher S-TG and S-Glu but lower S-Urate was revealed at baseline in type 2 diabetes women and men as compared to their counterparts, non-diabetes patients. Women with type 2 diabetes had higher S-Ca and lower S-Mg than non-diabetes women. Changes in S-Glu were associated with changes in S-Ca (+), baseline S-Ca (+), and S-Urate (-) in type 2 diabetes men. Changes in S-Urate were associated with changes in S-Mg (+) in type 2 diabetes women and non-diabetes men. In men with non-diabetes, changes in S-Glu were associated with changes in S-Mg (-). In women with non-diabetes, changes in S-Glu were associated with changes in S-P (-) and changes in S-Urate with changes in S-Ca (+). Conclusion: With respect to metabolic disturbances in non-diabetes and the awareness of risk for type 2 diabetes, changes in S-Glu and changes in S-Ca, S-Mg, and S-P should be considered as risk factors for cardiovascular disease. Increased early detection and corrections of high S-Ca, low S-Mg, and S-P in obese patients may improve their metabolism and reduce the risk of CVD in patients with type 2 diabetes. Trial registration number: ISRCTN: ISRCTN79355192

  • 161.
    Håglin, Lena
    et al.
    Umeå University, Faculty of Medicine, Public Health and Clinical Medicine, Family Medicine.
    Törnkvist, Birgitta
    Umeå University, Faculty of Social Sciences, Statistics.
    Backman, Lennart
    Faculty of Medicine, Public Health and Clinical Medicine.
    Prediction of all-cause mortality in a patient population with hypertension and type 2 DM by using traditional risk factors and serum-phosphate, -calcium and -magnesium.2007In: Acta Biabetologica, ISSN 0940-5429 (Print) 1432-5233 (Online), Vol. 44, no 3Article in journal (Refereed)
    Abstract [en]

    The aim of this study is to investigate whether the prediction of all-cause mortality from traditional risk factors is improved by adding electrolytes (serum-phosphate (S-P), serum-calcium (S-Ca) and serum-magnesium (S-Mg)) in a Cox regression. The study uses an 18-year follow-up of patients (n=2504) referred by physicians in primary health care and hospitals to the Vindeln Patient Education (VPE) Center, mainly with a diagnosis of hypertension (HT), type 2 diabetes mellitus (DM) and/or obesity.

    Cox regression, with the latest registered value and baseline values for risk factors, was used to study all-cause mortality in men and women. 221 out of 1096 men and 157 out of 1408 women died during the 18-year follow-up (20% and 11% respectively). The Cox regression analysis reveals that high blood glucose (B-Glu) and low S-Mg were significantly associated with increased all-cause mortality in the whole patient population as well as in men and women separately. Among women, type 2 DM and systolic blood pressure (SBP) and among men, high S-Ca, S-P, S-urate and body mass index (BMI) were the main predictors of all-cause mortality. There is significantly improved prediction of all-cause mortality with electrolytes added to the traditional risk factors. High B-Glu and low S-Mg in both men and women, and high S-Ca and S-P in men, are significantly associated with all-cause mortality. The metabolic disturbance in this high-risk group of patients can be more fully understood if ionic imbalance is included in the prediction of mortatlity.

  • 162.
    Hållberg, Bengt
    Umeå University, Faculty of Social Sciences, Statistics.
    Statistiska modeller för banbrottsfrekvens hos tryckpapper1976Doctoral thesis, monograph (Other academic)
  • 163.
    Högberg, Ulf
    et al.
    Umeå University, Faculty of Medicine, Public Health and Clinical Medicine, Epidemiology and Global Health.
    Broström, Göran
    Umeå University, Faculty of Social Sciences, Department of Statistics.
    The demography of maternal mortality-seven Swedish parishes in the 19th century1986In: International Journal of Gynecology & Obstetrics, ISSN 0020-7292, E-ISSN 1879-3479, Vol. 24, p. 37-44Article in journal (Refereed)
  • 164.
    Högberg, Ulf
    et al.
    Umeå University, Faculty of Medicine, Public Health and Clinical Medicine, Epidemiology and Global Health.
    Wall, Stig
    Umeå University, Faculty of Medicine, Public Health and Clinical Medicine, Epidemiology and Global Health.
    Broström, Göran
    Umeå University, Faculty of Social Sciences, Department of Statistics.
    The impact of early medical technology on maternal mortality in late 19th century Sweden1986In: International Journal of Gynecology & Obstetrics, ISSN 0020-7292, E-ISSN 1879-3479, Vol. 24, p. 251-261Article in journal (Refereed)
  • 165.
    Ingrid, Svensson
    Umeå University, Faculty of Social Sciences, Statistics.
    Självreflektion: En del av gruppkursutvärderingar?2008In: Om examination och lärande, Växjö University , 2008, p. 154-Chapter in book (Refereed)
  • 166.
    Isaksson, Cristine
    et al.
    Umeå University, Faculty of Social Sciences, Department of Social Work.
    Lindkvist, Marie
    Umeå University, Faculty of Social Sciences, Department of Statistics.
    Svensson, Ingrid
    Umeå University, Faculty of Social Sciences, Department of Statistics.
    När två blir ett: en lyckosam integrering av kurser i kvalitativ och kvantitativ metod i ett unikt samarbete mellan Statisktiska institutionen och institutionen för Socialt arbete2010In: Undervisning på tvären / [ed] Erik Lindenius, 2010, p. 77-92Conference paper (Refereed)
    Abstract [sv]

    Sedan höstterminen 2006 ges en integrerad kurs i kvalitativ och kvantitativ metod på socionomprogrammet vid Umeå universitet. Tidigare ansvarade institutionen för Socialt arbete för en kvalitativ metodkurs och Statistiska institutionen för en kvantitativ metodkurs. Under hösten 2005 kom direktiv från Ledningsgruppen för socionomprogrammet att en integrerad metodkurs skulle startas med början höstterminen 2006. Med integrering som ledord lämnades de kursansvariga från respektive institution med uppdraget att utveckla och genomföra denna nya form av metodkurs - en integrerad metodkurs som saknade motsvarighet vid såväl Umeå universitet som andra lärosäten i Sverige. Kursens pedagogiska upplägg utgår från teorier kring experimentellt lärande vilket tydliggörs genom att kursen är uppbyggd kring en processövning som löper under hela kursen och som integrerar praktiska moment med teori. Arbetet med processövningen sker i grupper om 5-7 studenter. Under de fem terminer som kursen getts har ett intensivt förändrings- och utvecklingsarbete utförts av lärarna på Statistiska institutionen och Institutionen för Socialt arbete. Både studenter och undervisande lärare uttrycker att de är nöjda med det pedagogiska upplägget av den integrerade metodkursen. Genom integreringen har förutsättningar skapats för en fördjupad reflektion hos studenterna kring fördelarna med att använda båda de vetenskapliga angreppssätten kvalitativ och kvantitativ metod.

  • 167.
    Ivarsson, Anneli
    et al.
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Epidemiology and Global Health.
    de Luna, Xavier
    Umeå University, Faculty of Social Sciences, Department of Statistics.
    Nilsson, Karina
    Umeå University, Faculty of Social Sciences, Department of Sociology.
    Lindgren, Urban
    Umeå University, Faculty of Social Sciences, Department of Social and Economic Geography.
    Bergdahl, Ingvar
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Registerdata om barndomen: kunskapsbas för hållbar hälsa och välfärd2010In: SVEPET. Medlemsbladet för Svensk Epidemiologisk Förening (Svep), Vol. 28, no 3, p. 4-6Article in journal (Other academic)
  • 168.
    Johansson, Mikael
    et al.
    Umeå University, Faculty of Social Sciences, Department of Statistics.
    Jönsson, Erik
    Umeå University, Faculty of Social Sciences, Department of Statistics.
    Evaluating a cumulative voting process: An analysis of different approaches2010Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 169.
    Josefsson, Maria
    et al.
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE), Statistics. Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    de Luna, Xavier
    Umeå University, Faculty of Social Sciences, Department of Statistics.
    Pudas, Sara
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI).
    Nilsson, Lars-Göran
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB).
    Nyberg, Lars
    Umeå University, Faculty of Medicine, Umeå Centre for Functional Brain Imaging (UFBI). Umeå University, Faculty of Social Sciences, Centre for Population Studies (CPS). Umeå University, Faculty of Medicine, Department of Integrative Medical Biology (IMB), Physiology.
    Genetic and lifestyle predictors of 15-Year longitudinal change in episodic memory2012In: Journal of The American Geriatrics Society, ISSN 0002-8614, E-ISSN 1532-5415, Vol. 60, no 12, p. 2308-2312Article in journal (Refereed)
    Abstract [en]

    OBJECTIVES: To reveal distinct longitudinal trajectories in episodic memory over 15 years and to identify demographic, lifestyle, health-related, and genetic predictors of stability or decline. DESIGN: Prospective cohort study. SETTING: The Betula Project, Umeå, Sweden. PARTICIPANTS: One thousand nine hundred fifty-four healthy participants aged 35 to 85 at baseline. MEASUREMENTS: Memory was assessed according to validated episodic memory tasks in participants from a large population-based sample. Data were analyzed using a random-effects pattern-mixture model that considered the effect of attrition over two to four longitudinal sessions. Logistic regression was used to determine significant predictors of stability or decline relative to average change in episodic memory. RESULTS: Of 1,558 participants with two or more test sessions, 18% were classified as maintainers and 13% as decliners, and 68% showed age-typical average change. More educated and more physically active participants, women, and those living with someone were more likely to be classified as maintainers, as were carriers of the met allele of the catechol-O-methyltransferase gene. Less educated participants, those not active in the labor force, and men were more likely to be classified as decliners, and the apolipoprotein E ɛ4 allele was more frequent in decliners. CONCLUSION: Quantitative, attrition-corrected assessment of longitudinal changes in memory can reveal substantial heterogeneity in aging trajectories, and genetic and lifestyle factors predict such heterogeneity.

  • 170.
    Karlsson, Maria
    Umeå University, Faculty of Social Sciences, Department of Statistics.
    Analysis of interpurchase intervals of cars using truncated and censored data2005Report (Other academic)
    Abstract [en]

    Knowledge of consumer behaviour is important to companies and governmental authorities for, e.g, planning purposes. In this paper the relationship between interpurchase intervals of  cars and demographic and economic characteristics of the car owners are analysed. Data was collected within a panel study of households in Sweden. Due to the study design, data is left truncated and right censored. The degree of censoring was almost 80 percent which made estimation of the models challenging. Results show that income and age of the car owners are important for the length of the interpurchase intervals of cars. Moreover, the results imply that models recommended for interpurchase intervals of durable goods in general might be inappropriate for interpurchase intervals of cars. A generalized gamma distribution, which embeds several distributions, is used to model interpurchase intervals. Semiparametric models are also considered.

  • 171.
    Karlsson, Maria
    Umeå University, Faculty of Social Sciences, Department of Statistics.
    Estimators of regression parameters for truncated and censored data2006In: Metrika, ISSN 1435-926X, Vol. 63, no 3, p. 329-341Article in journal (Refereed)
    Abstract [en]

    Estimators of parameters in semi-parametric left truncated and right censored regression models are proposed. In contrast to the majority of existing estimators, the proposed estimators do not require the error term of the regression model to have a symmetric distribution. In addition the estimators use asymmetric “trimming” of observations. Consistency and asymptotic normality of the estimators are shown. Finite sample properties are considered in a small simulation study. For the left truncated case, an empirical application illustrates the usefulness of the estimator.

  • 172.
    Karlsson, Maria
    Umeå University, Faculty of Social Sciences, Department of Statistics.
    Estimators of semiparametric truncated and censored regression models2005Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis contributes in several ways to the existing knowledge on estimation of truncated, censored, and left truncated right censored (LTRC) regression models. Three new semiparametric estimators are proposed, allowing for asymmetric error distributions. A bootstrap method for estimation of the covariance matrix of the quadratic mode estimator (QME) is proposed and studied. In addition, finite sample properties of estimators for truncated, censored, and LTRC data are studied within simulation studies and applications with real data.

    The first paper consists of a simulation study of the QME and other estimators of truncated regression models. The paper contributes with results suggesting the bootstrap technique being potentially useful for estimation of the QME covariance matrix.

    In the second paper estimators of truncated and censored semiparametric regression models are proposed. These estimators are generalizations of the QME and the winsorized mean estimator (WME) by allowing asymmetric ``trimming'' of observations. Consistency and asymptotic normality of the estimators are shown.

    By combining the two moment restrictions used to derive the estimators in the second paper, a consistent estimator of LTRC regression models is proposed in the third paper.

    The fourth paper contains an application where LTRC interpurchase intervals of cars are analysed. Results regarding the interpurchase behaviour of consumers are provided, as are results on estimator properties.

  • 173.
    Karlsson, Maria
    Umeå University, Faculty of Social Sciences, Department of Statistics.
    Finite sample properties of the QME2004In: Communications in statistics. Simulation and computation, ISSN 0361-0918, E-ISSN 1532-4141, Vol. 33, no 3, p. 567-583Article in journal (Refereed)
    Abstract [en]

    Bias and MSE of the QME are studied by means of simulation. A bootstrap estimator of the QME covariance matrix is also included in the study. The simulation is based on travel distances reported in the Swedish Travel Habit Survey. The results are in accordance with the asymptotic properties of the QME. For example, the QME is better than other suggested estimators under asymmetric distributions of the error term. The results also suggest that the bootstrap technique is potentially useful for estimation of the QME covariance matrix.

  • 174.
    Karlsson, Maria
    Umeå University, Faculty of Social Sciences, Statistics.
    Skattning av regressionsparametrar med trunkerade och censurerade data2006In: Quartilen, Vol. 21, no 1, p. 11-14Article in journal (Other academic)
  • 175.
    Karlsson, Maria
    et al.
    Umeå University, Faculty of Social Sciences, Department of Statistics.
    Cantoni, Eva
    University of Geneva, Department of Econometrics.
    de Luna, Xavier
    Umeå University, Faculty of Social Sciences, Department of Statistics.
    Local polynomial regression with truncated or censored response2009Report (Other academic)
    Abstract [en]

    Truncation or censoring of the response variable in a regression model is a problem in many applications, e.g. when the response is insurance claims or the durations of unemployment spells. We introduce a local polynomial re­gression estimator which can deal with such truncated or censored responses. For this purpose, we use local versions of the STLS and SCLS estimators of Powell (1986) and the QME estimator of Lee (1993) and Laitila (2001). The asymptotic properties of our estimators, and the conditions under which they are valid, are given. In addition, a simulation study is presented to investigate the finite sample properties of our proposals.

  • 176.
    Karlsson, Maria
    et al.
    Umeå University, Faculty of Social Sciences, Department of Statistics.
    Laitila, Thomas
    Umeå University, Faculty of Social Sciences, Department of Statistics.
    A semiparametric regression estimator under left truncation and right censoring2008In: Statistics and Probability Letters, ISSN 0167-7152, E-ISSN 1879-2103, Vol. 78, no 16, p. 2567-2571Article in journal (Refereed)
    Abstract [en]

    An estimator is proposed for semiparametric linear regression models with left truncated and right censored dependent variables. The estimator is derived from a moment condition following the principles of Newey [Newey, W.K., 2001. Conditional moment restrictions in censored and truncated regression models. Econometric Theory 17, 863–888] on conditional moment conditions. Consistency of the estimator is shown and simulation is used for illustration of the small sample properties.

  • 177. Kriström, Bengt
    et al.
    Laitila, Thomas
    Umeå University, Faculty of Social Sciences, Statistics.
    Stated preference methods for environmental valuation: a critical look2003In: The International Yearbook of Environmental and Resource Economics 2003/2004: A Survey of Current Issues, 2003Chapter in book (Refereed)
  • 178.
    Kvarnström, Björn
    et al.
    Luleå University of Technology, Luleå, Sweden.
    Bergquist, Bjarne
    Luleå University of Technology, Luleå, Sweden.
    Vännman, Kerstin
    Umeå University, Faculty of Social Sciences, Department of Statistics.
    RFID to improve traceability in continuous granular flows: an experimental case study2011In: Quality Engineering, ISSN 0898-2112, E-ISSN 1532-4222, Vol. 23, no 4, p. 343-357Article in journal (Refereed)
    Abstract [en]

    Traceability is important for identifying the root causes of production-related quality problems. Traceability can often be reached by adding identification markers on products, but this is not a solution when the value of the individual product is much lower than the incurred cost of a marking system. This is the case for continuous production of granular media. The use of radio frequency identification (RFID) techniques to achieve traceability in continuous granular flows has been proposed in the literature. We study through experiments different methods to improve the performance of such an RFID system. For example, larger transponders and multiple readers are shown to improve the RFID system performance.

  • 179.
    Laitila, Thomas
    Umeå University, Faculty of Social Sciences, Statistics.
    Estimation in Truncated and Censored Regressions1989Doctoral thesis, monograph (Other academic)
  • 180.
    Laitila, Thomas
    et al.
    Umeå University, Faculty of Social Sciences, Department of Statistics.
    Marell, gneta
    Umeå University, Faculty of Social Sciences, Umeå School of Business and Economics (USBE).
    Westin, Kerstin
    Umeå University, Faculty of Social Sciences, Department of Social and Economic Geography.
    Taxitrafikens egenskaper och taxikundernas uppfattning fyra år efter avregleringen1995Report (Other academic)
  • 181.
    Laitila, Thomas
    et al.
    Umeå University, Faculty of Social Sciences, Statistics.
    Paulrud, Anton
    A Multi-Attribute Extension of Discrete-Choice Contingent Valuation for Valuation of Angling Site Characteristics2006In: Journal of Leisure Research, Vol. 38, no 2, p. 133-142Article in journal (Refereed)
  • 182.
    Laitila, Thomas
    et al.
    Umeå University, Faculty of Social Sciences, Department of Statistics.
    Westin, Kerstin
    Umeå University, Faculty of Social Sciences, Department of Social and Economic Geography.
    Miljöhänsyn vid val av godstransportör2000Report (Other academic)
  • 183.
    Laitila, Thomas
    et al.
    Umeå University, Faculty of Social Sciences, Department of Statistics.
    Westin, Kerstin
    Umeå University, Faculty of Social Sciences, Department of Social and Economic Geography.
    Utvärdering av några analystekniker vid Stated Preference-undersökningar1997Report (Other academic)
  • 184.
    Landfors, Mattias
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Clinical Bacteriology. Umeå University, Faculty of Science and Technology, Department of Mathematics and Mathematical Statistics.
    Fahlén, Jessica
    Umeå University, Faculty of Social Sciences, Department of Statistics.
    Rydén, Patrik
    Umeå University, Faculty of Social Sciences, Department of Statistics. Umeå University, Faculty of Science and Technology, Department of Mathematics and Mathematical Statistics.
    MC-normalization: a novel method for dye-normalization of two-channel microarray data2009In: Statistical Applications in Genetics and Molecular Biology, ISSN 1544-6115, E-ISSN 1544-6115, Vol. 8, no 1, p. 42-Article in journal (Refereed)
    Abstract [en]

    Motivation: Pre-processing plays a vital role in two-color microarray data analysis. An analysis is characterized by its ability to identify differentially expressed genes (its sensitivity) and its ability to provide unbiased estimators of the true regulation (its bias). It has been shown that microarray experiments regularly underestimate the true regulation of differentially expressed genes. We introduce the MC-normalization, where C stands for channel-wise normalization, with considerably lower bias than the commonly used standard methods.

    Methods: The idea behind the MC-normalization is that the channels’ individual intensities determine the correction, rather than the average intensity which is the case for the widely used MA-normalization. The two methods were evaluated using spike-in data from an in-house produced cDNA-experiment and a public available Agilent-experiment. The methods were applied on background corrected and non-background corrected data. For the cDNA-experiment the methods were either applied separately on data from each of the print-tips or applied on the complete array data. Altogether 24 analyses were evaluated. For each analysis the sensitivity, the bias and two variance measures were estimated.

    Results: We prove that the MC-normalization has lower bias than the MA-normalization. The spike-in data confirmed the theoretical result and suggest that the difference is significant. Furthermore, the empirical data suggest that the MC-and MA-normalization have similar sensitivity. A striking result is that print-tip normalizations did have considerably higher sensitivity than analyses using the complete array data.

  • 185.
    Legrell, P E
    et al.
    Umeå University, Faculty of Medicine, Department of Odontology, Oral and Maxillofacial Radiology.
    Nyquist, H
    Umeå University, Faculty of Social Sciences, Department of Statistics.
    Isberg, A
    Umeå University, Faculty of Medicine, Department of Odontology, Oral and Maxillofacial Radiology.
    Validity of identification of gonion and antegonion in frontal cephalograms2000In: Angle orthodontist, ISSN 0003-3219, E-ISSN 1945-7103, Vol. 70, no 2, p. 157-64Article in journal (Refereed)
    Abstract [en]

    This study was designed to develop a method of transferring gonion from lateral to frontal cephalograms, and to use this method as gold standard when evaluating observer performance in identifying gonion in frontal cephalograms. Observer ability to identify antegonion was also evaluated. There was a range of 28 mm in the observers' identification of gonion and a statistically significant deviation from gold standard. The factors "observer" and "cephalogram," regarded as random effects in an ANOVA analysis, and their interaction, each influenced the result, P < .001. The deviation from the mean of all observations for antegonion ranged 8 mm with "cephalogram" having a statistically significant influence. The results suggest that neither gonion nor antegonion can be routinely used as valid landmarks in frontal cephalograms. Gonion can, however, be used if first identified in a lateral cephalogram and transferred to a paired frontal cephalogram aided by radiographic indicators combined with a bilateral scrutiny of projection geometry in different planes through gonion and indicator.

  • 186.
    Lindberg, Fredrik
    Umeå University, Faculty of Social Sciences, Department of Statistics.
    Den demografiska utvecklingen i dagens Sverige: Konsekvenser för den framtida försörjningsbördan2010Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
  • 187.
    Lindgren, Urban
    et al.
    Umeå University, Faculty of Social Sciences, Social and Economic Geography.
    Strömgren, Magnus
    Umeå University, Faculty of Social Sciences, Social and Economic Geography.
    Holm, Einar
    Umeå University, Faculty of Social Sciences, Social and Economic Geography.
    Häggström Lundevaller, Erling
    Statistics. Umeå University, Faculty of Social Sciences, Social and Economic Geography.
    Analyzing Socio-Economic Impacts of Large Investments by Spatial Microsimulation2007In: 1st General Conference of the International Microsimulation Association: Celebrating 50 Years of Microsimulation, 2007Conference paper (Other academic)
    Abstract [en]

    In the near future, a nuclear waste repository will be located in either Östhammar or Oskarshamn, two Swedish municipalities. This is a major investment that is likely to have socio-economic implications at the local level for several decades. In order to analyze the indirect local effects of such large investments, a spatial and dynamic microsimulation model (SVERIGE 3) has been constructed. The model simulates demographic events (e.g., fertility and migration) as well as education and the labor market. In this study, the simulation model is utilized to evaluate a number of scenarios comprising various potential investments in Östhammar, one of which is the nuclear waste repository. As part of the study, the direct local effect of the investments was estimated. When running the model, the estimated direct local effects function as exogenous economic input to concerned labor market sectors. The results of the simulations indicate that investments such as the nuclear waste repository will have some economic and demographic effects. However, infrastructure projects that increase accessibility seem to generate more profound and long-lasting effects at the local level. A municipality such as Östhammar, located close the Stockholm metropolitan area, may be especially likely to benefit by such infrastructure investments.

  • 188.
    Lindkvist, Marie
    Umeå University, Faculty of Social Sciences, Statistics.
    Added Variable Plots and sensitivity in Cox's Regression Model2000Doctoral thesis, monograph (Other academic)
  • 189.
    Lindkvist, Marie
    et al.
    Umeå University, Faculty of Social Sciences, Statistics.
    Broström, Göran
    Umeå University, Faculty of Social Sciences, Statistics.
    Clustered infant mortality in an intergenerational perspective, Skellefteå 1831--18902006Conference paper (Other (popular science, discussion, etc.))
  • 190.
    Lindkvist, Marie
    et al.
    Umeå University, Faculty of Social Sciences, Statistics. Umeå University, Faculty of Social Sciences, Statistics.
    Broström, Göran
    Umeå University, Faculty of Social Sciences, Statistics. Umeå University, Faculty of Social Sciences, Statistics.
    Interaction between fertility and infant mortality in an intergenerational perspective2008In: ESSHC Conference in Lisbon, 26 February-1 March, 2008, 2008Conference paper (Refereed)
    Abstract [en]

    Many studies in the past have emphasized the positive correlation between infant mortality and fertility, but how this operates remain unclear. In this paper, we investigate these interdependent processes using data from the Demographic Data base at Ume{\aa} University. More specifically, we have data from regions in the northern part of Sweden, starting in the fifteenth century and ending around the year 1900. In an earlier paper, we have studied the intergenerational aspects of infant mortality and in this paper we incorporate fertility. We investigate the interaction between the two processes and how patterns are tranferred from generation to generation.

  • 191.
    Lindkvist, Marie
    et al.
    Umeå University, Faculty of Social Sciences, Statistics. Umeå University, Faculty of Social Sciences, Statistics.
    Broström, Göran
    Umeå University, Faculty of Social Sciences, Statistics.
    Partial partial likelihood2005Report (Other academic)
  • 192.
    Lindmark, Anita
    Umeå University, Faculty of Social Sciences, Department of Statistics.
    Reliabilitet hos metoder för mätning av avstånd mellan sekvenser: En simuleringsstudie i R-paketet TraMineR2010Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
  • 193.
    Lundberg, Anna
    et al.
    Umeå University, Faculty of Social Sciences, The Demographic Database.
    Svensson, Ingrid
    Umeå University, Faculty of Social Sciences, Centre for Population Studies. Umeå University, Faculty of Social Sciences, Department of Statistics.
    Restored to Society - The Recovering of Mentally Ill Patients in the Northern Parts of Sweden 1893-19022009In: Healthcare Systems and Medical Instiutions / [ed] Astri Andresen, Oslo: Novus AS , 2009Chapter in book (Other academic)
  • 194.
    Lundgren, Anders
    et al.
    Umeå University, Faculty of Social Sciences, Social and Economic Geography.
    Häggström Lundevaller, Erling
    Statistics. Umeå University, Faculty of Social Sciences, Social and Economic Geography.
    Micro-Simulation Modeling of Domestic Tourism Travel Patterns in Sweden2004In: The Second International Conference on: Monitoring and Management of Visitor Flows in Recreational and Protected Areas, 2004Conference paper (Other (popular science, discussion, etc.))
  • 195.
    Lundgren, Anders
    et al.
    Umeå University, Faculty of Social Sciences, Social and Economic Geography.
    Häggström Lundevaller, Erling
    Statistics. Umeå University, Faculty of Social Sciences, Social and Economic Geography.
    Müller, Dieter
    Umeå University, Faculty of Social Sciences, Social and Economic Geography.
    Modeling Domestic Tourism in Sweden2007In: Tourism Analysis, Vol. 11, pp 349-366., ISSN 1083-5423, Vol. 11, no 6, p. 349-366Article in journal (Refereed)
    Abstract [en]

    In this paper it is demonstrated how a microsimulation model based on TDB-data (Swedish Tourist Database provided by Marknadsfakta, Åre, Swe¬den) can be used to estimate the number of trips, choice of activity and choice of destination for domestic overnight trips in Sweden using individual micro data from Statistics Sweden. It is argued that this modeling on the micro-level accounts for changes in population structure and geography to a far greater extent than conventional models because of its focus on individual behavior in relation to individual socio-economic characteristics. Thus, changes in the supply of tourism results in changing travel patterns. Also changes in the population and its spatial distribution are mirrored directly in the resulting travel pattern.

  • 196.
    Lundin, Mathias
    Umeå University, Faculty of Social Sciences, Department of Statistics.
    Effects of college choice on income: estimation and sensitivity analysis2006Licentiate thesis, monograph (Other academic)
  • 197.
    Lundin, Mathias
    Umeå University, Faculty of Social Sciences, Department of Statistics.
    Effects of college choice on income in SwedenManuscript (preprint) (Other academic)
  • 198.
    Lundin, Mathias
    Umeå University, Faculty of Social Sciences, Department of Statistics.
    Profile likelihood for semiparametric regressionManuscript (preprint) (Other academic)
  • 199.
    Lundin, Mathias
    Umeå University, Faculty of Social Sciences, Department of Statistics.
    Sensitivity Analysis of Untestable Assumptions in Causal Inference2011Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis contributes to the research field of causal inference, where the effect of a treatment on an outcome is of interest is concerned. Many such effects cannot be estimated through randomised experiments. For example, the effect of higher education on future income needs to be estimated using observational data. In the estimation, assumptions are made to make individuals that get higher education comparable with those not getting higher education, to make the effect estimable. Another assumption often made in causal inference (both in randomised an nonrandomised studies) is that the treatment received by one individual has no effect on the outcome of others. If this assumption is not met, the meaning of the causal effect of the treatment may be unclear.

    In the first paper the effect of college choice on income is investigated using Swedish register data, by comparing graduates from old and new Swedish universities. A semiparametric method of estimation is used, thereby relaxing functional assumptions for the data.

    One assumption often made in causal inference in observational studies is that individuals in different treatment groups are comparable, given that a set of pretreatment variables have been adjusted for in the analysis. This so called unconfoundedness assumption is in principle not possible to test and, therefore, in the second paper we propose a Bayesian sensitivity analysis of the unconfoundedness assumption. This analysis is then performed on the results from the first paper.

    In the third paper of the thesis, we study profile likelihood as a tool for semiparametric estimation of a causal effect of a treatment. A semiparametric version of the Bayesian sensitivity analysis of the unconfoundedness assumption proposed in Paper II is also performed using profile likelihood.

    The last paper of the thesis is concerned with the estimation of direct and indirect causal effects of a treatment where interference between units is present, i.e., where the treatment of one individual affects the outcome of other individuals. We give unbiased estimators of these direct and indirect effects for situations where treatment probabilities vary between individuals. We also illustrate in a simulation study how direct and indirect causal effects can be estimated when treatment probabilities need to be estimated using background information on individuals.

  • 200.
    Lundin, Mathias
    et al.
    Umeå University, Faculty of Social Sciences, Department of Statistics.
    Karlsson, Maria
    Umeå University, Faculty of Social Sciences, Department of Statistics.
    Estimation of causal effects in observational studies with interference between units2014In: Statistical Methods & Applications, ISSN 1618-2510, E-ISSN 1613-981X, Vol. 23, no 3, p. 417-433Article in journal (Refereed)
    Abstract [en]

    Causal effects are usually estimated under the assumption of no interference between individuals. This assumption means that the potential outcomes for one individual are unaffected by the treatments received by other individuals. In many situations, this is not reasonable to assume. Moreover, not taking interference into account could result in misleading conclusions about the effect of a treatment. For two-stage observational studies, where treatment assigment is randomized in the first stage but not in the second stage, we propose IPW estimators of direct and indirect causal effects as defined by Hudgens and Halloran (J Am Stat Assoc 103(482):832-842, 2008) for two-stage randomized studies. We illustrate the use of these estimators in an evaluation study of an implementation of Triple P (a parenting support program) within preschools in Uppsala, Sweden.

1234567 151 - 200 of 303
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf