Five objectives were set for the development of this instrument: (1) good content and face validity; (2) short administration time; (3) simple scoring of clearly understandable items; (4) acceptable reliability; and (5) acceptable construct and concurrent validity.
The first round of CIs of the 35-item questionnaire found the items understandable, relevant, and readable on the whole across severity groups.
The first scale, labelled message acceptance (α = 0.889) was made up of two items: understandable and believable.
Given the rigor of these requirements, with a few notable exceptions (e.g., pain ratings), it is perhaps understandable why many single item measures tend to broadband measures of a general construct, since such items are largely unaffected by unexplained variance associated with individual and situational differences.
The response options were endorsed as understandable and matching the item stem by the end of the third wave of interviews.
Nine general practitioners were asked to evaluate the questionnaire to determine whether each item was understandable, whether the content of an item was important for care of chronically ill patients, and whether any important aspects were missing.
The structured guideline for the FG was to answer questions concerning: a) whether an item was understandable, b) whether the content of an item was important concerning care of chronically ill patients and c) whether there were any important aspects missing regarding care of the chronically ill in Germany.
It is therefore understandable that the three items should be clustered with the neuropathic pain subscale rather than items about numbness (loss of sensation) in the feet or hands of the neurological sensory subscale.
Likewise, the topic familiarity test was presented to content validators prior to the testing date to ascertain whether the items were within the scope of the topic under study and whether or not the items were understandable and within the level of the students being tested.
Overall, the BASSPID contained one scale, which had strong content and convergent validity as well as items easily understandable for individuals with an intellectual disability.
