Development of a Japanese Scale that Evaluates the Level of Nursing Support Provided to Patients for Decision-Making in Cancer Clinical Trials

Clinical nurses need learning programs that are useful in nursing support for patients' decision-making (NSPDM) regarding cancer clinical trials (CCTs). The usefulness of the learning program can be evaluated if the practices of NSPDM before and after participation in the learning program can be compared. We developed a scale to measure the level of self-assessed NSPDM regarding participation in a CCT. Thirty-two items of scale were developed in Japanese based on previous literature. Based on the results of a pilot study, items with similar meanings were removed and the validity of the 26 scale items was statistically examined in terms of construct validity and reliability. The study population was clinical nurses and included clinical research nurses. We received 102 valid responses from clinical nurses. Based on the bias of the boxplot distribution and the ceiling and floor effects for the items analysis of the 26-item draft scale, 17 items remained. Exploratory factor analysis (EFA) revealed that the scale consisted of three subscales and 17 items. Regarding fit indices of the model, the goodness-of-fit index (GFI), adjusted GFI (AGFI), comparative fit index (CFI), and root mean square error of application (RMSEA) were 0.775, 0.704, 0.477, and 0.081, respectively. The Cronbach's alpha coefficient for the overall scale was 0.951, with subscales ranging from 0.820 to 0.942. The validity and reliability of this scale were acceptable. This scale may be helpful to evaluate the usefulness of learning programs, i.e., the practice level of NSPDM.