Health Status Measures: Strategies and Analytic Methods for Assessing Change Scores

Assessing the need for health status measures.

Rare Outcomes, Common Treatments: Analytic Strategies Using Propensity Scores

Propensity Scores When treated patients are compared to controls, differing outcomes may reflect either effects caused by the treatment or differences in prognosis before treatment. Random assignment of patients to treatment or control, as in a randomized, controlled clinical trial (1), ensures that the groups were comparable before treatment and the prognosis in treated and control groups was ...

Rare outcomes, common treatments: analytic strategies using propensity scores.

Propensity Scores When treated patients are compared to controls, differing outcomes may reflect either effects caused by the treatment or differences in prognosis before treatment. Random assignment of patients to treatment or control, as in a randomized, controlled clinical trial (1), ensures that the groups were comparable before treatment and the prognosis in treated and control groups was ...

Reproducibility and responsiveness of health status measures. Statistics and strategies for evaluation.

Before being introduced to wide use, health status instruments should be evaluated for reliability and validity. Increasingly, they are also tested for responsiveness to important clinical changes. Although standards exist for assessing these properties, confusion and inconsistency arise because multiple statistics are used for the same property; controversy exists over how to measure responsiv...

Epidemiologic Methods of Assessing Asthma and Wheezing Episodes in Longitudinal Studies: Measures of Change and Stability

BACKGROUND In settings in which diseases wax and wane, there is a need to measure disease dynamics in longitudinal studies. Traditional measures of disease occurrence (eg, cumulative incidence) do not address change or stability or are limited to stable cohorts (eg, incidence) and may thus lead to erroneous conclusions. To illustrate how different measures can be used to detect disease dynamics...