Characteristics of the PRO instruments, including the number of items, concepts measured, and scoring method, are presented in Table 2.
Although Ling and colleagues [ 14] addressed issues with the B&B Scale by having patients report directly on pelvic pain, dysmenorrhea, and dyspareunia daily using a 0 to 10 numeric rating scale (NRS), no qualitative research involving patient input to support the item concept and response scale selection was conducted.
General appreciation was measured by eight items, monetary appreciation was measured by five items (see Concepts and corresponding questionnaire items).
In the article, the authors tested the internal reliability (using Cronbach's α) of each set of items (attitudes, concepts, and skills) within the survey to see whether it would be reasonable to analyze each set of items as three separate scales.
Items which caused problems (e.g. ambiguity, wording) were discussed with two of the developers of the original MSSS-88 scale (J.C. Hobart, A. Riazi) to ensure the original item concepts were maintained and to clarify unclear aspects.
The questionnaire included 24 items regarding knowledge of preventive measures (15 items), concept of (opinion regarding) institutional measures (4 items), and perception of risk (5 items) (Appendix).
The instructions and items of the EXACT questionnaire were well understood by both groups, and all patients generally interpreted and described all item concepts in a consistent way.
Once the common items and concepts were identified, and their comparability assessed at follow-up, item scores could be standardized in the baseline cohorts to provide a common metric.
Another approach to testing the construct validity of some aspect of the MDS is to examine the relationship between selected items and concepts which the literature and clinical practice tells us should be related to readily measured "objective" outcomes like death or hospitalization.
The prior-knowledge test consisted of three questions with six items regarding basic concepts and methods for solving optimization problems.
