a. Systematic identification of existing PRO instruments meeting explicit eligibility criteria.
b. Selection of additional instruments (e.g. generic instruments) to be administered alongside the new PRO instrument.
c. All items from the identified instruments form the initial 'item pool' (to which Steps 2-5 are applied).
Item de-duplication. Items are discarded if:|
A) They are literal duplications (identically worded items, or duplication of item content)
B) Their content differs only by timeframe or attribution to a condition of interest (e.g. do you have difficulty... because of your condition)
C) Their content overlaps with generic measures to be administered alongside new instrument (e.g. SF-36)
D) Macro level: items discarded if associated with content themes (dimensions of health) that are not appropriate for inclusion in the new instrument (e.g. treatment satisfaction)
E) Micro level: application of explicit, study-relevant criteria to select items for inclusion in draft instrument (actual content area)
|Step 4||Assessment of content coverage against a relevant pre-existing theoretical framework (revisit 3E if content coverage suboptimal)|
|Step 5||Exploratory pilot work with target population to assess comprehensibility, acceptability, relevance and answerability in order to inform instrument refinement (item removal &/or re-wording) (e.g.'think aloud' study, focus groups)|