Attrition, or the loss of study subjects, confounds the subject identification process. Design attrition occurs when subjects initially involved in the study are excluded because of changes in study focus or rationale. Data collection attrition occurs when subjects are excluded because they were not contacted by the data gatherer, or because the…

A two-year study assessed the progress of 119 females and 368 males who declared premedicine as their major during their freshman and sophomore years at the University of Iowa. Data from follow-up questionnaires indicate that a similar number of men and women planned to apply to medical schools, contrary to expectations. (LBH)

Comparable groups of undergraduate students, withdrawers and persisters, were surveyed and compared in terms of their self-perceived parental expectations of academic success. Students who entered college directly from high school reported greater parental expectations of success than transfer students. Withdrawers reported less parental…

Reviews attrition rates in bereavement research and demonstrates prevalence of low acceptance rates and lack of knowledge about bias due to self-selection. Reports results of empirical study which showed effect of depression on willingness to participate: widowers who were less depressed agreed to participate; widows who were more depressed were…

The relationships among grade, substance assessed, and type of measurement and statistical analysis used in the detection of external validity threats resulting from subject attrition in a modal follow-up study were examined in 6 successive 2-year panels of adolescents, including 4,819 overall stayers and 1,897 dropouts. (SLD)

A strategy proposed by T. Cook and D. Campbell (1979) was used to investigate attrition in a community-based literacy program, focusing on 287 Head Start families. Data revealed interactions among intervention program-centered characteristics and person-centered characteristics that have implications for study validity and generalizability.…

Purpose: The purpose of this study was to determine strength gains following expiratory muscle strength training (EMST) and to determine detraining effects when the training stimulus is removed. Method: Thirty-two healthy participants were enrolled in an EMST program. Sixteen participants trained for 4 weeks (Group 1) and 16 participants trained…

This paper explores the question of why some beginning teachers terminate employment in the first 2 years and others do not. The investigation will be conceptually organized around the concepts presented in Becker and Carper's theoretical framework (1956). They identify four elements that beckon and retain individuals in an occupation: (1)…

Selective subject attrition from longitudinal study panels can bias estimates of developmental change. Particularly in studies of older adults, sampling effects can adversely affect attempts to estimate true ontogenetic change. Selective attrition effects were examined in 636 Pennsylvania adults (138 males, 498 females), aged 58-91, who were…

In a longitudinal study, subject attrition constitutes a potential threat to the usefulness of data collected from subjects remaining in later waves of the study. If attrition is selective, then the sample at later waves of the study may be representative of a different population than that represented at the outset of the study. This study…

The follow-up of participants in a longitudinal survey can be difficult and expensive. This paper reviews the experiences of Project TALENT's 11-year follow-up survey of 400,000 individuals tested as high school students in 1960 and the experiences of follow-ups in other longitudinal studies. Methods for minimizing sample attrition and detecting…

It is difficult to conduct randomized field experiments. In the past decade, the use of alternative randomization plans and incentives has contributed to their operational feasibility; legal, ethical, and professional arguments for experimentation have matured; and expectations have become better aligned with practical constraints that are likely…

Factors associated with completing a follow-up interview in an AIDS outreach/intervention project targeting out-of-treatment crack smokers were studied through 409 baseline interviews and 288 follow-up interviews. The study demonstrates that access to hard-to-reach subjects for follow-up is possible. Methods to enhance follow-up rates are…

Methods of using simplified time series analysis (STSA) in evaluating clinical programs are discussed. STSA assists in addressing problems of attrition/augmentation of subjects in programs with changing populations. Combining individually calculated "C" statistics in a simple aggregate analysis of restraint usage by nursing home staff…

Arguing that reliable and valid dropout rate estimates are prerequisite to establishment of causal factors and intervention programs, this article examines differences in definitions of dropouts, computational methods, and the complexities in defining cohorts, as well as the importance of sample attrition. Several sources of error are discussed.…