Eight items of the ruminative response scale are sufficient to measure weekly within-person variation in rumination

The Ruminative Response Scale (RRS) is commonly used to measure people’s general tendency to ruminate. In this study, we explored whether only few items from the RRS can be used to capture within-person variation in rumination in intensive longitudinal studies. Such a short RRS version would allow, for example, monitoring the development of rumination during clinical interventions. We measured rumination on five occasions, with at least one week in between. We used multilevel analyses to analyze the data at the within- and between-person level. Using only eight RRS items, we successfully modeled a reflective self-regulation and depressive brooding factor, similar to the two subfacets of rumination as distinguished by Treynor et al. (2003). We also established convergent validity of depressive brooding at the within- and between-person level of analysis and convergent validity of reflection at the between-person level. We thus introduced a short form of the RRS that captures within-person variation in depressive brooding and reflection well. The short RRS is readily applicable in studies on within-person variation or change in rumination.