Selection of the most suitable instrument for a health outcome or exposure assessment is challenging, as there are many different instruments and their versions, most with unknown validity.
To develop guidelines facilitating the search for the most suitable instrument.
Based on our experience, we formalised a five-step process. The first step is the search for systematic reviews of available instruments validity in COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN), International prospective register of systematic reviews (PROSPERO), or conventional (eg, Medline and Web of Science) databases. If there is no systematic review, the clinician should look for original validation studies and assess them critically. We presented two alternatives of this assessment: qualitative using COSMIN and quantitative using our methodological framework. The latter helps to decide upon the instrument validity completeness and interpret the statistical results from original studies objectively. This process was then transformed into guidelines, which were tested by three external clinicians to select the most appropriate instrument to measure depression, occupational stress and daily fatigue.
The guidelines were proved to facilitate the instrument search and selection, practical and time-saving.
The guidelines assessment highlighted that clinicians should check whether the instrument that they are looking for was developed for screening or diagnosing purposes, whether it can be self-administered or not, and for which setting it was validated (academic vs clinical).
These guidelines facilitate the objective choice of the most suitable instrument in clinical practice by making the search simple, systematic and time-effective.