4.3 Methodological standards of included COSs
For COS-STAD checklist, more than 95% of COSs met all four standards for scope specification. In addition, most clearly described the research or practice setting in which COS was applied, and the health condition, population, and intervention covered by the COS. The decision as to which outcomes are core to measure, and why is an important process. Fourteen COSs (31.8%) met all the three standards for the domain of stakeholders involved; based on the author affiliations or participant lists, twenty-four (54.5%) of COSs were developed by people intending to use the COS in research, and health care professionals with experience of patients with the condition; sixteen COSs (36.4%) did not describe the inclusion of patients with the condition or their representatives. All the stakeholders involved in the COS development should be reported to ascertain whether the COS fully reflects the views of important outcomes for the target population in the forthcoming research. This would be conducive to the utilization and promotion of the COS.23 Given the difficulty to judge the standards of COS-STAD in the consensus process that was set in advance, we determined whether the studies that met this standard rely on the registration information and published protocol.19Only 27.3% of COSs priori described a consensus protocol, and some registration information was inadequately reported, making it difficult to judge whether some standards were set prior. We suggest that the registration platform could improve the standards for COS registration, thereby promoting the integrity and transparency of COS developed. 92.1% of COSs did not report whether the patient representatives received a glossary of terms before completing the survey, which may cause ambiguity of language. Compared with COSs without prior protocol or registered detailed, those studies with a priori protocol or registered detailed had higher compliance rates of “describe consensus definition” and “criteria for including/dropping/adding outcomes consensus process in advance.” Besides, we found that COSs developed with statistical or epidemiologist authors incorporated the views of healthcare professionals on important outcomes. Compared to cancer COSs, OG COSs similarly had a high compliance rate for standards in the scope domain, and low compliance rates for the standards in the field of stakeholders involved and consensus process.19