Objective: To determine which environmental factors are associated with performance when controlling for capacity, using the International Classification of Functioning, Disability and Health (ICF).
Methods: A psychometric study using a sample of 296 persons with musculoskeletal health conditions as a case in point. The following steps were carried out: (i) Rasch analyses created 2 interval measurement scales, capacity and performance, based on 22 Activities and Participation ICF categories that had been rated as capacity and performance. Capacity and performance scores, ranging from 0 (low level) to 100 (high level) were calculated; (ii) group lasso regression was used to identify the environmental factors associated with a person's performance when controlling for capacity. Gender, age and health condition were forced to remain in the model.
Results: A capacity scale based on 16 ICF categories (rated as capacity) and a performance scale based on 18 categories (rated as performance) were created. Thirteen environmental factors ICF categories covering the physical, social, attitudinal and political environment were identified as highly associated with patient's performance.
Conclusion: Using an exclusively statistical approach this study identified environmental factors associated with a person's performance.