Results 31 to 40 of about 1,716,816 (278)
Spontaneous breaking of rotational symmetry in the presence of defects [PDF]
, 2013 We prove a strong form of spontaneous breaking of rotational symmetry for a simple model of two-dimensional crystals with random defects in thermal equilibrium at low temperature.
Heydenreich, Markus +2 more
core +2 more sources
BMC Medical Research Methodology, 2019 Background In many clinical trials continuous outcomes are dichotomized to compare proportions of patients who respond. A common and recommended approach to handling missing data in responder analysis is to impute as non-responders, despite known biases.
Lysbeth Floden, Melanie L. Bell
doaj +1 more source
Little's Test of Missing Completely at Random [PDF]
The Stata Journal: Promoting communications on statistics and Stata, 2013 In missing-data analysis, Little's test (1988, Journal of the American Statistical Association 83: 1198–1202) is useful for testing the assumption of missing completely at random for multivariate, partially observed quantitative data. I introduce the mcartest command, which implements Little's missing completely at random test and its extension for ...
Li, Cheng, Li, Cheng
openaire +2 more sources
Comparison of Different LGM-Based Methods with MAR and MNAR Dropout Data
Frontiers in Psychology, 2017 The missing not at random (MNAR) mechanism may bias parameter estimates and even distort study results. This study compared the maximum likelihood (ML) selection model based on missing at random (MAR) mechanism and the Diggle–Kenward selection model ...
Meijuan Li +5 more
doaj +1 more source
Problems in dealing with missing data and informative censoring in clinical trials
Current Controlled Trials in Cardiovascular Medicine, 2002 A common problem in clinical trials is the missing data that occurs when patients do not complete the study and drop out without further measurements. Missing data cause the usual statistical analysis of complete or all available data to be subject to ...
Shih Weichung
doaj +1 more source
Biased Estimation of Adjusted Odds Ratios From Incomplete Covariate Data Due to Violation of the Missing at Random Assumption [PDF]
, 1996 We investigate the possible bias due to an erroneous missing at random assumption if adjusted odds ratios are estimated from incomplete covariate data using the maximum likelihood principle.
Illi, S., Vach, W.
core +2 more sources
Evaluation of missing data mechanisms in two and three dimensional incomplete tables
, 2018 The analysis of incomplete contingency tables is a practical and an interesting problem. In this paper, we provide characterizations for the various missing mechanisms of a variable in terms of response and non-response odds for two and three dimensional
Ghosh, S., Vellaisamy, P.
core +1 more source
BMC Medical Research Methodology, 2019 Background A number of strategies have been proposed to handle missing binary outcome data (MOD) in systematic reviews. However, none of these have been evaluated empirically in a series of published systematic reviews. Methods Using published systematic
Loukia M. Spineli
doaj +1 more source
Missing data and multiple imputation in clinical epidemiological research [PDF]
, 2017 Missing data are ubiquitous in clinical epidemiological research. Individuals with missing data may differ from those with no missing data in terms of the outcome of interest and prognosis in general. Missing data are often categorized into the following
Cronin-Fenton, D +6 more
core +1 more source
Pediatric Blood &Cancer, EarlyView.ABSTRACT Purpose Cognitive and psychological difficulties could negatively interfere with treatment adherence and quality of life before and after hematopoietic stem cell transplant (HSCT). Methods to mitigate these changes may have positive effects on treatment success.
Kristen L. Votruba +11 more
wiley +1 more source