Table 2 Quality assessment tool for evaluation of PROMs modified from Pesudovs et al. [24] and Hamzah et al. [20]

Pre-study hypothesis

The pre-study specification of the aim of the instrument and the intended population

√√ A clear description is provided of the aim of the instrument and the intended population

√ Only one of the above

X Neither reported

Intended population

The extent to which the instrument has been studied in the intended population

√√ Intended population studied

√ Partly studied only or sample size was small (less than 50 patients)

X Not studied in the intended population, only generic

Actual content area

The extent to which the content meets the pre-study hypothesis specifications

√√ Content is intended and is relevant to the intended population

√ Some of the intended content areas are missing

X Content areas are not relevant to the intended population

Item identification

Selection of the items relevant to the target population for inclusion in the pilot instrument

√√ Comprehensive consulting with patients (focus groups or in-depth interviews) and a literature review

√ Minimal consultation with patients and expert opinion and literature review

X No consultation with patients

Item selection

Determining the items included in the final instrument

√√ A pilot instrument was developed and tested with Rasch or factor analysis and statistical justification provided for removing items, plus items with floor and ceiling effects removed and the amount of missing data considered

√ Only one of the above techniques were used

X No pilot instrument OR no statistical justification of items included in the final instrument

Scoring

A description of how the instrument should be scored

√√ Rasch scoring of a statistically justified response scale

√ Summary scoring of a statistically justified response scale

X Scoring system not described or scoring of a statistically unjustified or faulty scale