Quality assessment tool for theory-based and literature review studies (QATTL): development and validation of a critical appraisal tool

A recognised challenge in undertaking a systematic review is critical appraisal of study quality. Tools have been developed for assessing quantitative, qualitative, and mixed methods studies. However, critical appraisal of theory-based and literature review studies is not similarly supported. This study develops and validates a tool designed for appraisal of theory-based and literature review studies using 1,181 single appraisals and 496 aggregated paired appraisals. The findings supported a two-factor model for quality appraisal that emphasized core quality items (title, abstract, introduction, literature, theoretical framework, findings, and discussion) and supplementary data (conclusions, disclosures, strengths and limitations, and use of tables and figures). The Quality Assessment Tool for Theory-based and Literature review studies (QATTL) can be incorporated into systematic review studies that include theory-based and literature studies in their sample. This paper provides a clear model for assessing the quality of theory and literature review studies and information on key parameters of quality for the design of literature reviews.