Q&A with B. Price Kerfoot, MD EdM: How Long Do the Benefits of Qstream Last?

In a new blog series, Qstream co-founder and Spaced Education expert B. Price Kerfoot MD EdM answers some of the frequently asked questions we receive about how our solution improves knowledge retention and changes behaviors in just minutes a day. Have a question for our expert? Email us at

How long do the benefits of Qstream last?

Qstream employs the Spaced Education methodology that we developed, tested and implemented at Harvard Medical School over the last 10 years. We have conducted over 20 large randomized trials to assess the efficacy of the methodology, and three in particular provide some insight on how long the benefits of Spaced Education last: 

(1) Kerfoot BP, Fu Y, Baker H, Connelly D, Ritchey ML, Genega EM.  Online spaced education generates transfer and improves long-term retention of diagnostic skills: a randomized, controlled trial. J Am Coll Surg. 2010 Sep;211(3):331-337.
In this study, 724 urology residents were randomized to receive instruction on pathology either via spaced education or via web-based teaching modules (AKA ‘binge-and-purge’ learning). The content delivered to the doctors in each cohort was identical, with the only difference being the method of delivery. We then monitored their retention of the material for 29 weeks after the instruction was completed. While those who received the instruction via web-based modules showed a large spike in performance (yes, cramming can work), their learning quickly faded back to baseline just a few weeks after the instruction. In contrast, the spaced education generated learning that was retained much more effectively over the 29 weeks (6+ months) following the instruction.

(2) Kerfoot BP, Lawler EV, Sokolovskaya G, Gagnon D, Conlin PR. Durable improvements in prostate cancer screening from online spaced education a randomized controlled trial. Am J Prev Med 2010;39:472-8.
In this study, 95 primary care clinicians in the northeastern US were randomized to two cohorts. Clinicians in cohort 1 received a spaced education program over 36 weeks covering when and when not to screen for prostate cancer, while those in cohort 2 received no intervention (thus representing the current standard of medical care for prostate cancer screening). Once the instruction concluded, we monitored how the clinicians in both cohorts screened for prostate cancer over 72 weeks. We found that the spaced education clinicians ordered significantly fewer inappropriate screening tests compared to controls (7.8% vs 13.1%, respectively, p=0.011), representing a 40% relative reduction in inappropriate screening. In addition, the impact of the spaced education on clinicians’ screening behaviors showed no appreciable decline over these 72 weeks (~18 months) of follow-up.

 (3) Kerfoot BP. Learning benefits of online spaced education persist for two years. J Urol 2009; 181, 2671-2673.

In 2005, we conducted a randomized trial of spaced education among 537 urology residents that showed it to be an effective educational tool among these doctors. Two years later, 206 (38%) of the doctors from the first trial were still in training. We retested this subset of doctors on the same content and found that those who had received the content via spaced education in 2005 had significantly greater retention of the material than the controls in 2007.

In summary, these three trials show that spaced education can generate meaningful and sustained improvements in knowledge retention for 6, 18, and 24 months, respectively. Although we do not have data assessing the impact of spaced education beyond 24 months, it is certainly possible that the improvements generated by spaced education persist even longer than 2 years.

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