R package to identify sudden gains

Abstract

Sudden gains are large and stable changes on an outcome variable between consecutive measurements, for example during a psychological intervention with multiple assessments. Researching these occurrences could help understand individual change processes in longitudinal data. Tang and DeRubeis (1999) suggested three criteria to define sudden gains in psychological interventions. However, identifying sudden gains based on these criteria can be time consuming and prone to errors if not fully automated. Further, methodological decisions such as how missing data, or multiple gains, are handled vary across studies and are reported with different levels of detail. These problems limit the comparability of individual studies and make it hard to understand or replicate the exact methods used. The R package suddengains provides a set of tools to facilitate sudden gains studies by automating their identification, adjusting for missing data, and providing descriptive statistics as well as exportable data files for further analysis. Keywords: sudden gains, sudden losses, R, mechanisms of change, processes of change, psychological therapy, longitudinal analysis, single case designs suddengains: An R package to identify sudden gains in longitudinal data