Summary Individuals with chronic stroke are characterized by low levels of walking activity, which negatively impacts post-stroke health and the risk for recurrent stroke. Although walking speed and endurance are logical targets for improving walking activity, improving them alone rarely translates to more walking activity in the free-living environment in this group. Individuals with chronic stroke also have low falls efficacy, which includes their confidence in performing daily activities without falling. Evidence suggests that, if the low falls efficacy of those with chronic stroke is not addressed, the benefits of improved walking capacity on walking activity won’t be realized. To date, falls efficacy has been quantified as an aggregate score from self-reported questionnaires, such as the Activities-specific Balance Confidence (ABC) scale. A challenge to addressing falls efficacy after stroke is that it is likely comprised of distinct balance domains not reflected by an aggregate score. These balance domains, including anticipatory control, walking balance, and reactive balance, can be considered independent targets for rehabilitation. The ABC scale contains questions relevant to each of these domains. By aggregating the score, however, the ABC scale does not inform the specific balance intervention targets that could be used to address falls efficacy and, subsequently, walking activity. Our study aims are to 1) demonstrate that the construct of falls efficacy in those with chronic stroke is comprised of multiple factors representing distinct balance domains, and 2) demonstrate that falls efficacy has specific, factor-based relationships with walking activity in those with chronic stroke. These aims will be addressed using secondary analyses of ABC scale data within the University of Delaware Stroke Studies Registry, as well as baseline ABC scale and sensor-based walking data from a multi-site clinical trial in those with chronic stroke (PI: Reisman). To address the first aim, we will conduct a factor analysis of ABC scale questions to objectively identify unique domains within the falls efficacy construct. To address the second aim, we will predict walking activity volume, frequency, intensity, and sedentary behavior from factor-specific ABC scale data. The results of this study will advance the specificity and utility of the ABC scale in characterizing falls efficacy, as well as informing domain- specific balance targets for improving falls efficacy and walking activity.