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Neuro-QOL's primary goal is the development of a comprehensive item bank for patient-reported outcomes of neurological disorders. Based upon input from patients, experts and the published literature, we chose to focus on pain, fatigue, emotional distress, physical function, and social function. A useful step in the development of an item pool is the identification, evaluation, and revision of extant questionnaire items for the core item pool. This process includes classification of questions in the item pool into content categories for subsequent statistical analysis.
Six phases of item development are documented: identification of extant items, item classification and selection, item review and revision, focus group input on domain coverage, cognitive interviews with patients regarding their understanding of individual items, and final revision before field testing. Identification of items refers to the systematic search for existing questions in currently available scales. Expert item review and revision was conducted by trained professionals who reviewed the wording of each question and revised as appropriate for conventions adopted by the Neuro-QOL group. Focus groups were used to confirm domain definitions, and to identify new areas of item development for future item banks. Cognitive interviews were used to examine individual items. Questions that survived this process were sent to field testing and will be evaluated psychometrically for inclusion in item banks or targeted scales for Neuro-QOL.
Selection and Development of Items
Instruments and items were identified by Neuro-QOL investigators and expert consultants by literature searches and previous item banking projects. These items were delivered to a central Neuro-QOL Item Library. Over 3,000 items were entered into the Neuro-QOL Item Library, including information on the time frame of the response requested, the exact wording of the item stem and response options, and any context (e.g., specific instructions) for the respondent to consider when answering the question. Once the Neuro-QOL item library was populated, items were assigned to the Neuro-QOL domains through an iterative, multi-step process involving at least three domain experts. Two (2) independent raters worked collaboratively to sort items into sub-domains, using sub-domain content driven by item review. All discrepancies in the sub-domain allocations made by the 2 reviewers were reconciled by a 3rd reviewer to ensure consistency across domains. As the number of items (many of which were redundant) that existed in the library was large, all items were reviewed to determine if they should proceed through detailed item review/revision/testing and were grouped together according to each domain’s hierarchy of sub-domains, factors, and facets.
Once all items were assigned to respective domains, content experts "winnowed" (or systematically removed items) from items pools because of semantic redundancy, availability of a superior alternative, inconsistency with domain definition, wrong domain assignment, vague or confusing language, cultural/translation relevance, gender inappropriateness, narrowness of content, or excessive disease specificity. Items selected from winnowing underwent a more thorough review done collaboratively by two domain co-chairs and several outside content experts. Most items needed revision for general consistency across banks. Re-writing or generating new items was done to assure comprehensiveness in measuring the domain; clear, understandable and precise language to experts and respondents; amenability to linguistic translation; and adaptability to the data collection and analysis strategies planned. Findings from individual cognitive interviews and dataset analyses were provided to content groups to integrate into decision making. During this process, items from PROMIS (Patient Reported Outcomes Measurement Information System) and AM-PAC (Activity Measure for Post Acute Care), were compared with Neuro-QOL items and redundancy was eliminated. Final item pools were reviewed by patients with the Neuro-QOL conditions (n=63) during telephone-based cognitive interviews in English and Spanish to assess the content validity of items, clarify concepts, and refine language and response options. During interviews patients reviewed each item in a one-on-one semi-structured interview focused on item comprehension and relevance. Patients and experts also identified areas (gaps in domain) for new item development and creation, to which new items were written or revised. See Figure 2 for an overview of the item identification and selection process.
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