A guide to the measurement and interpretation of fMRI test-retest reliability. (August 2021) - Noble, Stephanie
Highlights: Context is needed to appreciate recent reports of poor univariate fMRI reliability. We provide a guide to measuring and interpreting fMRI test-retest reliability via ICC. We discuss factors that influence reliability, highlighting better multivariate than univariate reliability. Test-retest reliability is not the only goal and validity must also be considered. Recent findings should motivate better practices but do not invalidate existing work. Abstract : The test-retest reliability of functional neuroimaging data has recently been a topic of much discussion. Despite early conflicting reports, converging reports now suggest that test-retest reliability is poor for standard univariate measures — namely, voxel-based and region-level task-based activation and edge-level functional connectivity. To better understand the implications of these recent studies requires understanding the nuances of test-retest reliability as commonly measured by the intraclass correlation coefficient (ICC). Here we provide a guide to the measurement and interpretation of test-retest reliability in functional neuroimaging and review major findings in the literature. We highlight the importance of making choices that improve reliability so long as they do not diminish validity, pointing to the potential of multivariate approaches that improve both. Finally, we discuss the implications of recent reports of low test-retest reliability in the context of ongoing work in the field.