What is OMERACT?Conference
OMERACT strives to improve endpoint outcome measurement through a data driven, iterative consensus process involving relevant stakeholder groups. The term OMERACT was originally established in 1992 to mean “Outcome Measures in Rheumatoid Arthritis Clinical Trials”. Since then the OMERACT initiative has turned into an international informal network, with working groups and gatherings interested in outcome measurement across the spectrum of rheumatology intervention studies. The acronym has therefore been broadened to now stand for 'Outcome Measures in Rheumatology'.

How does OMERACT work?
To reach consensus over what should be measured, and how, i.e., what measures are applicable in trials for each clinical Attendeesindication, OMERACT has developed the following procedure. First, the organizing committee polls experts and opinion leaders to generate interest in the topic at hand. These individuals then form a committee to guide the subsequent process. From the general domains of health status defined by the "D's" (Discomfort, Disability, Dollar Cost, Death), specific domains are formulated for the topic in question. In each domain, measures are collected and tested for their applicability. The domains and the applicable measures form the basis for the consensus guidelines. The process is data-driven and iterative, and has evolved over the past 16 years. Although not needed when OMERACT was small and the same individuals were involved, as OMERACT has grown and new individuals take on the leadership of taskforces, we have found it helps to break down the process into the different stages of Special Interest Groups, Workshops and Modules.

When is a measure "endorsed by OMERACT "?
A measure is "endorsed” when it passes the OMERACT Filter in its intended setting.
The OMERACT Filter has three component criteria: Truth, Discrimination, and Feasibility. Each component criteria represents a question to be answered of the measure, in each of its intended settings:

1. Truth: is the measure truthful, does it measure what it intends to measure? Is the result unbiased and relevant? This criterion captures the issues of face, content, construct and criterion validity.

2. Discrimination: does the measure discriminate between situations that are of interest? The situations can be states at one time (for classification or prognosis) or states at different times (to measure change). This criterion captures the issues of reliability and sensitivity to change.

3. Feasibility: can the measure be applied easily, given constraints of time, money, and interpretability? This criterion addresses the pragmatic reality of the use of the measure, one that may be decisive in determining a measure's success.

What has been achieved?
These 8 OMERACT conferences have succeeded in achieving consensus on core sets of measures for rheumatoid arthritis, osteoarthritis and osteoporosis, psoriasis/ psoriatic arthritis [GRAPPA], on psychosocial measures, core set of data for cost-effectiveness evaluations, and an agreed metric to score and report MRI findings in rheumatoid arthritis (RAMRIS).  Taskforces are ongoing in working towards consensus in Surrogate Endpoints in Rheumatology Trials, and Psoriatic Arthritis. Workshops were held on  MRI in Ankylosing Spondylitis (AS),  Fibromyalgia, Fatigue, Repair in RA, Radiographs / Joint Space Narrowing, Vasculitis, Drug Safety, Scleroderma, Work Productivity,  Item Response Theory & Computer Adaptive Testing, Gout, Low Back Pain, Baseline State in RA, Economic Reference Case in AS, Virtual total articular replacement as outcome, Ultrasound,  Synovial Tissue, Chemical Biomarkers, MRI in inflammatory arthritis,  Single joint response, the  Effective Consumer Scale.