BACKGROUND: The congruence or discordance between actual and perceived balance ability has been proposed to be linked to functional outcomes such as falls. However, gaps remain in our ability to quantify discordance, and its relationship to relevant outcomes. OBJECTIVE: To investigate a novel quantification of concordance/discordance between balance performance and perception and determine the relationship to falls among people with Parkinson's disease (PwPD). METHODS: Data from 244 PwPD were aggregated from 5 previously conducted studies. Variables extracted included age, sex, Activities-Specific Balance Confidence scale (ABC
perceived balance), Timed Up and Go (TUG
balance performance), Movement Disorder Society Unified Parkinson Disease Rating Scale (MDS-UPDRS) part III scores, and retrospective falls (6- or 12-month). Data validation between studies was established. Discordance was quantified as the difference between an individual's predicted ABC, based upon their TUG score, to their reported ABC. RESULTS: Two methods for calculating discordance were tested: simple linear regression and segmented regression. As there were no differences between the bootstrap distributions of both approaches ( CONCLUSIONS: Discordance between actual and perceived balance was uniquely related to retrospective fall history among PwPD. Clinicians and researchers should consider discordance between actual and perceived balance as a potentially modifiable target to minimize falls.