Data extraction and quality assessment
Two authors independently screened all entries (KG and BD). Where
protocols had been published, study characteristics, proposed
methodology and consensus methods were recorded. The quality of
published COS protocols was assessed using the COS-STAP.(13) Where
authors had published systematic reviews, the study characteristics,
methodology and results were collated. If a COS was published, study
characteristics, methodology for potential core outcome identification,
consensus methods used to determine final COS were collated. The
methodological and reporting quality of the COS development process was
assessed using the COS-STAD and the COS-STAR.(14, 15). A green rating
was given when all criteria in the specific domain were achieved, red
where they were not fulfilled and yellow if fulfilment was unclear.
Emails were sent to registered authors if no publications could be found
to identify potential grey literature, or if the milestones proposed by
the authors during the COMET initiative registration process had passed.