Response by Ahmad et al to Letter Regarding Article, “Validity of Cardiovascular Data From Electronic Sources: The Multi-Ethnic Study of Atherosclerosis and HealthLNK”

We appreciate the interest of Mewton et al in our work.1 We agree with the assertion that fundamental differences exist in the data collection and verification processes in traditional clinical studies (either observational cohort studies or clinical trials) and those from large healthcare databases. However, the issues with data quality exist across all research methodologies. For example, the time- and resource-intensive methods used in traditional cohort studies often rely primarily on participant self-report, which can result in underreporting. Our work highlights the overlap, discordance, strengths, and limitations of a traditional community cohort compared with an electronic data research network. …