We think we can: Development of the Dyadic Efficacy Scale for Cancer

Background: Measurement advances are needed to enable the study of dyadic-level processes impacting couples coping with cancer. This study sought to develop and empirically examine a Dyadic Efficacy Scale for Cancer (DESC). Cancer-related dyadic efficacy is an individual's confidence to work together with a partner to cope with cancer and its treatment. Methods: The DESC was developed using an exploratory sequential mixed methods design. This paper outlines the psychometric evaluation phase. Individuals with cancer (N = 261) and their partners (N = 217) completed 50 items. Item-level analyses reduced this set to 26 items. Using the dyad as the unit of analysis, confirmatory factor analysis with mirrored patient and partner bifactor structure tested for the presence of a general factor and 3 secondary factors, that is, illness intrusions, patient affect, partner affect. Results: Goodness-of-fit indices supported the identified model, χ 2 (1170) = 2090, P < .001; RMSEA = .05, P = .14, 90% CI.05-.06; SRMR = .05; CFI = .90. Multidimensionality differed for patients and partners. A general dyadic efficacy factor and secondary factors for managing affect were present for both dyad members, whereas the secondary factor of managing illness intrusions was confirmed for patients only. The model explained 72% and 64% of the variance in patients' and partners' dyadic efficacy. Evidence of convergent validity was presented. Conclusions: This study is the first to provide a tool to assess dyadic efficacy among couples coping with cancer. The assessment of cancer-related dyadic efficacy enables new discoveries into couples' adjustment to cancer.