Development of an item bank and computer adaptive test for role functioning

Role functioning (RF) is a key component of health and well-being and an important outcome in health research. The aim of
this study was to develop an item bank to measure impact of health on role functioning.

A set of different instruments including 75 newly developed items asking about the impact of health on role functioning was
completed by 2,500 participants. Established item response theory methods were used to develop an item bank based on the generalized
partial credit model. Comparison of group mean bank scores of participants with different self-reported general health status
and chronic conditions was used to test the external validity of the bank.

After excluding items that did not meet established requirements, the final item bank consisted of a total of 64 items covering
three areas of role functioning (family, social, and occupational). Slopes in the bank ranged between .93 and 4.37; the mean
threshold range was −1.09 to −2.25. Item bank-based scores were significantly different for participants with and without
chronic conditions and with different levels of self-reported general health.

An item bank assessing health impact on RF across three content areas has been successfully developed. The bank can be used
for development of short forms or computerized adaptive tests to be applied in the assessment of role functioning as one of
the common denominators across applications of generic health assessment.