Black individuals are underrepresented in randomized clinical trials (RCTs). Willingness to participate is a frequently cited explanation. However, the few studies that have investigated willingness to participate demonstrated no difference between Black individuals and other groups. We sought to measure willingness to participate by focusing on sickle cell disease (SCD), in which approximately 90% of affected individuals are Black. We conducted an analysis of 17 RCTs. A level of clarity was defined and correlated with each article's transparency in reporting patient enrollment data. Calculated measures of acceptance ranged from 32% to 93.5%. Calculated completion rates ranged from 58.8% to 100%. Weighted measures of acceptance and completion were 59.1% and 83.8%, respectively. Our study is limited by focusing solely on studies pertinent to SCD and only a minority of publications reviewed provided sufficient patient enrollment data. Yet, our results suggest that decreased willingness to participate does not account for underrepresentation of Black individuals.