The evolution of instrument selection for inclusion in core outcome sets at OMERACT: Filter 2.2

Introduction: OMERACT uses an evidence-based framework known as the 'OMERACT Filter Instrument Selection Algorithm' (OFISA) to guide decisions in the assessment of outcome measurement instruments for inclusion in a core outcome set for interventional and observational clinical trials. Methods: A group of OMERACT imaging and patient-centered outcome methodologists worked with imaging outcome groups to facilitate the selection of imaging outcome measurement instruments using the OFISA approach. The lessons learned from this work influenced the evolution to Filter 2.2 and necessitated changes to OMERACT's documentation and processes. Results: OMERACT has revised documentation and processes to incorporate the evolution of instrument selection to Filter 2.2. These revisions include creation of a template for detailed definitions of the target domain which is a necessary first step for instrument selection, modifications to the Summary of Measurement Properties (SOMP) table to account for sources of variability, and development of standardized reporting tables for each measurement property. Conclusions: OMERACT Filter 2.2 represents additional modifications of the OMERACT guide for working groups in their rigorous assessment of measurement properties of instruments of various types, including imaging outcome measurement instruments. Enhanced reporting aims to increase the transparency of the evidence base leading to judgements for the endorsement of instruments in core outcome sets. Keywords: Core outcome sets; Instrument selection; Methodology; OMERACT; Outcome measurement instruments; Rheumatic and musculoskeletal diseases.