Objective To assess to what extent the clinical trial policies of the largest public and philanthropic funders of clinical research in the United States meet WHO best practices in trial registration and reporting.

Methods Public and philanthropic funders of clinical trials in the USA with >US$50 million annual spend were selected. The funders were assessed using an 11-item scoring tool based on WHO Joint Statement benchmarks. These 11 items fell into 4 categories, namely: trial registration, academic publication, monitoring and sanctions. An additional item captured whether and how funders referred to Consolidated Standards of Reporting Trials (CONSORT) within their trial policies. Each funder was independently assessed by two or three researchers. Funders were contacted to flag possible errors and omissions. Ambiguous or difficult-to-score items were settled by an independent adjudicator.

Results Fourteen funders were assessed. Our cross-sectional study found that, on average, funders have only implemented 4.1/11 (37%) of WHO best practices in clinical trial transparency. The most frequently adopted requirement was open access publishing (14/14 funders). The least frequently adopted were (1) requiring trial ID to appear in all publications (2/14 funders, 14%) and (2) making compliance reports public (2/14 funders, 14%). Public funders, on average, adopted more policy elements (5.2/11 items, 47%) than philanthropic funders (2.8/11 items, 25%). Only one funder’s policy documents mentioned the CONSORT statement.

Conclusions There is a significant variation between the number of best practice policy items adopted by medical research funders in the USA. Many funders fell significantly short of WHO Joint Statement benchmarks. Each funder could benefit from policy revision and strengthening.