Sökning: "non-ignorable"

Hittade 4 avhandlingar innehållade ordet non-ignorable.

  1. 1. Uncertainty intervals and sensitivity analysis for missing data

    Författare :Minna Genbäck; Xavier de Luna; Elena Stanghellini; Arvid Sjölander; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; missing data; missing not at random; non-ignorable; set identification; uncertainty intervals; sensitivity analysis; self reported health; average causal effect; average causal effect on the treated; mixed-effects models; Statistics; statistik;

    Sammanfattning : In this thesis we develop methods for dealing with missing data in a univariate response variable when estimating regression parameters. Missing outcome data is a problem in a number of applications, one of which is follow-up studies. LÄS MER

  3. 2. Attrition in Studies of Cognitive Aging

    Författare :Maria Josefsson; Xavier de Luna; Lars Nyberg; Anders Lundquist; Mattias Villani; Umeå universitet; []
    Nyckelord :SAMHÄLLSVETENSKAP; SOCIAL SCIENCES; Attrition; missing data; age-related cognitive change; non- ignorable dropout; monotone missing pattern; mixture models; pattern- mixture models; imputation; Statistics; statistik;

    Sammanfattning : Longitudinal studies of cognition are preferred to cross-sectional stud- ies, since they offer a direct assessment of age-related cognitive change (within-person change). Statistical methods for analyzing age-related change are widely available. LÄS MER

  4. 3. Latent variable models for longitudinal twin data

    Författare :Annica Dominicus; Juni Palmgren; Nancy L. Pedersen; Michael G. Kenward; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Latent variable models; twin models; variance components; change point models; non-ignorable nonresponse; likelihood ratio tests; Mathematical statistics; Matematisk statistik;

    Sammanfattning : Longitudinal twin data provide important information for exploring sources of variation in human traits. In statistical models for twin data, unobserved genetic and environmental factors influencing the trait are represented by latent variables. In this way, trait variation can be decomposed into genetic and environmental components. LÄS MER

  5. 4. Translational and clinical aspects of pancreatic cancer

    Författare :Caroline Vilhav; Göteborgs universitet; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; pancreatic cancer; circulating tumor cells; extracellular vesicles; immunotherapy; PDX model; pancreaticoduodenectomy; postoperative complications; postpancreatectomy hemorrhage;

    Sammanfattning : Pancreatic cancer is a disease with dismal prognosis due to late detection and ineffective treatments. The majority of the patients already have disseminated disease at the time of diagnosis. The only potential curative treatment, surgery, is extensive with high morbidity and non-ignorable mortality. LÄS MER