PMH1: SHOULD THE 51 ITEMS OF THE SCHIZOPHRENIA OUTCOMES ASSESSMENT PROJECT (SOAP-51) BE WEIGHTED?

Abstract

OBJECTIVES: To determine if the 51 items in the Schizophrenia Outcomes Assessment Project (SOAP-51) instrument should be scored using weighted or unweighted items. METHODS: 193 community-based individuals with schizophrenia (average age 46.3yr, 46.6% female) rated the importance of each item in the SOAP-51 twice, 4 weeks apart, using a 10cm verbally anchored (?not important to me? to ?very important to me?), horizontal line with a numerical scale progressing in units of 10 from 0 (not)?100 (most). RESULTS: Results are based on 180 valid and complete surveys in the first administration; there were also 171 in the second. The items ranged from a low of 56.7 ± 35.5 (How important is it for you to have sexual relationships in your life?) to a high of 89.1 ± 18.4 (How important is it for you that your medication helps you?): 1 item scored in the 50s, 2 in the 60s, 16 in the 70s, and 33 in the 80s. Six of 8 average item factor scores (self-concept, work/role, mental health, medication effects, activities of daily living, and physical functioning) had weights in the 80s ranging from 80.4 ± 18.7 to 85.1 ± 13.3; however, two were in the 70s: 79.1 ± 15.5 (satisfaction) and 75.4 (interpersonal. There was no difference between the importance weights of the 8 factors nor the 51 items (p> 0.05). CONCLUSIONS: It is appropriate to use an unweighted summary for calculating the factor scores in the SOAP-51. It is apparent that in the SOAP item reduction process, items considered to be of import to the clients were retained in the final instrument.