Browsing by Subject "Longitudinal studies"
Now showing 1 - 3 of 3
- Results Per Page
- Sort Options
Item Approaches to modeling self-rated health in longitudinal studies : best practices and recommendations for multilevel models(2012-05) Sasson, Isaac; Powers, Daniel A.; Umberson, Debra J.Self-rated health (SRH) is an outcome commonly studied by demographers, epidemiologists, and sociologists of health, typically measured using an ordinal scale. SRH is analyzed in cross-sectional and longitudinal studies for both descriptive and inferential purposes, and has been shown to have significant validity with regard to predicting mortality. Despite the wide spread use of this measure, only limited attention is explicitly given to its unique attributes in the case of longitudinal studies. While self-rated health is assumed to represent a latent continuous and dynamic process, SRH is actually measured discretely and asymmetrically. Thus, the validity of methods ignoring the scale of measurement remains questionable. We compare three approaches to modeling SRH with repeated measures over time: linear multilevel models (MLM or LGM), including corrections for non-normality; and marginal and conditional ordered-logit models for longitudinal data. The models are compared using simulated data and illustrated with results from the Health and Retirement Study. We find that marginal and conditional models result in very different interpretations, but that conditional linear and non-linear models result in similar substantive conclusions, albeit with some loss of power in the linear case. In conclusion, we suggest guidelines for modeling self-rated health and similar ordinal outcomes in longitudinal studies.Item Longitudinal effects of working memory on internalizing and externalizing behavior problems(2010-08) Low, Justin Alan; Keith, Timothy, 1952-; Tharinger, Deborah; Carlson, Cindy; Beretvas, Susan; Anderson, EdwardSeveral research studies have examined the link between working memory ability and behavior problems in youth. Research suggests that children with working memory deficits demonstrate lower levels of attention and higher levels of hyperactivity, physical aggression, and other behavior problems. The purpose of this research was to determine the effects of developmental trajectories of working memory on the developmental trajectories of behavior problems. Results suggested that developmental increases in working memory did not lead to developmental decreases in behavior problems. Results from this study suggested that internalizing and externalizing behavior problems increase over the course of childhood. Several variables did lead to developmental change in behavior problems in children. Children who had lower initial levels of working memory increased in internalizing behaviors less than children with higher initial working memory ability. Also, high socioeconomic status led to smaller increases in internalizing and externalizing behavior, high Peabody Picture Vocabulary Test (PPVT) scores led to larger increases in internalizing and externalizing behavior, and high PPVT scores led to larger decreases in inattentive and hyperactive behavior. Results are discussed in reference to current theories about working memory and behavior problems.Item The role of measurement latency in interpreting outcomes of autism-focused early interventions(2022-05-24) Crank, Jenna E.; Sandbank, Micheal Paige; Hampton, Lauren; Cooc, North; Woynaroski, TiffanyEarly interventions often aim to affect developmental change over time. Many early interventions are structured in such a way as to affect change in immediate, proximal outcomes theorized to be developmentally significant with the hope that these improvements will affect positive change in distal outcomes over time through developmental cascades. This meta-analysis of 3,285 outcomes sourced from 252 studies investigates whether outcomes were moderated by the amount of time that passes between intervention onset, cessation, and point of outcome measurement, as well as whether there is an interaction effect of outcome proximity and measurement latency on intervention effects. The size of intervention effects were not moderated by measurement latency from intervention onset or cessation, and there was no significant interaction effect of proximity and latency, regardless of metric. However, outcomes considered to be ‘immediate’ measures (i.e., were measured less than 30 days after intervention cessation) were significantly larger than ‘follow-up’ outcomes (i.e., that were measured 30 or more days after intervention cessation). The confidence in these findings is tempered by reporting and sample quality concerns, and further investigation is needed to explore the role of the passage of time in interpreting the observed effectiveness of autism-focused early interventions.