BACKGROUND: Intention-to-treat (ITT) is an analytic approach where all randomized participants are included in analyses and in their originally assigned condition, regardless of adherence or protocol deviation.

PURPOSE: The present study aimed to determine whether reporting and correct use of ITT in behavioral medicine randomized clinical trials (RCTs) published in behavioral journals has improved in recent years.

METHOD: ITT and related analytic conventions were examined in behavioral medicine RCTs (N = 87) published in Annals of Behavioral Medicine, Health Psychology, and the Journal of Consulting and Clinical Psychology in the years 2000-2003 and then again in 2006-2007. Logistic regression analyses tested whether ten indicators associated with ITT were being used increasingly over time. Also tested was whether reporting and correct use of ITT improved following the adoption of Consolidated Standards of Reporting Clinical Trials (CONSORT) statement.

RESULTS: Results revealed that less than half of RCTs (42%) used ITT analyses correctly. Over time, reporting of sample size estimation and primary outcome as well as use of the term "ITT" to describe analyses improved; however, correct implementation of ITT did not. Improvement was not specifically attributable to CONSORT adoption.

CONCLUSION: Investigators' claims of using ITT analyses have increased over time, but correct use of ITT has not.