Buddy Arena is built on the two study methods with the strongest evidence.

Why a duel beats rereading the study guide

Rereading feels productive, but testing wins, and the gap shows up exactly when it matters: days and weeks later. In a 2006 study by Roediger and Karpicke, rereading looked better five minutes after studying, yet two days later the quizzed group was ahead, and at one week the gap had grown. If you fact-check us on this one, good. That instinct is why we cite everything.

Roediger, H. L., III, & Karpicke, J. D. (2006). Test-enhanced learning: Taking memory tests improves long-term retention. Psychological Science, 17(3), 249–255.

Rowland, C. A. (2014). The effect of testing versus restudy on retention: A meta-analytic review of the testing effect. Psychological Bulletin, 140(6), 1432–1463.

This works for healthcare professionals, not just undergrads

In a randomized trial with resident physicians learning clinical topics, repeated quizzing beat repeated studying by about 13 percentage points on a test six months later. That's the closest published population to working coders we know of.

Larsen, D. P., Butler, A. C., & Roediger, H. L., III. (2009). Repeated testing improves long-term retention relative to repeated study: A randomised controlled trial. Medical Education, 43(12), 1174–1181.

Why it's multiple choice (and why that's not a cop-out)

The CPC and CRC exams are 100 multiple-choice questions, so Buddy Arena practices the same format. A large meta-analysis found multiple-choice practice tests carried larger benefits (g = 0.70) than short-answer ones (g = 0.48). The same analysis found that a single practice test before a final produced larger effects (g = 0.70) than repeated practice tests of the same material (g = 0.51). That's why a concept you miss comes back as a different question, not the same one on repeat.

Adesope, O. O., Trevisan, D. A., & Sundararajan, N. (2017). Rethinking the use of tests: A meta-analysis of practice testing. Review of Educational Research, 87(3), 659–701.

Why every answer comes with the why

Two things go wrong without feedback. Hard quizzes teach almost nothing when you're scoring at or below 50 percent, and you can accidentally memorize a wrong code from a plausible distractor. So every Arena question shows the correct answer plus the rationale, citing the governing guideline. Explanations beat bare answers when you have to apply the rule to a new scenario, which is exactly what exam day is.

Butler, A. C., & Roediger, H. L., III. (2008). Feedback enhances the positive effects and reduces the negative effects of multiple-choice testing. Memory & Cognition, 36(3), 604–616.

Butler, A. C., Godbole, N., & Marsh, E. J. (2013). Explanation feedback is better than correct answer feedback for promoting transfer of learning. Journal of Educational Psychology, 105(2), 290–298.

Why the Daily Five exists and the leaderboard resets weekly

Spacing study across days beats cramming, and the right gap depends on how far away your test is. The Daily Five gives you a small spaced dose every day, and concepts you miss come back a few days later instead of right away, so the material stays fresh through exam day.

Cepeda, N. J., Pashler, H., Vul, E., Wixted, J. T., & Rohrer, D. (2006). Distributed practice in verbal recall tasks: A review and quantitative synthesis. Psychological Bulletin, 132(3), 354–380.

Cepeda, N. J., Vul, E., Rohrer, D., Wixted, J. T., & Pashler, H. (2008). Spacing effects in learning: A temporal ridgeline of optimal retention. Psychological Science, 19(11), 1095–1102.

Latimier, A., Peyre, H., & Ramus, F. (2021). A meta-analytic review of the benefit of spacing out retrieval practice episodes on retention. Educational Psychology Review, 33, 959–987.

Why duels mix topics instead of drilling one chapter

Telling near-miss codes apart is a discrimination skill, and mixed practice is strongest exactly when categories are confusable. In a classroom trial, the mixed-practice advantage grew from 16 points at one day to 32 points at 30 days. Every Arena draw spans multiple domains on purpose.

Brunmair, M., & Richter, T. (2019). Similarity matters: A meta-analysis of interleaved learning and its moderators. Psychological Bulletin, 145(11), 1029–1052.

Rohrer, D., Dedrick, R. F., & Stershic, S. (2015). Interleaved practice improves mathematics learning. Journal of Educational Psychology.

Why losing a duel on a topic you haven't studied is still a win

Guessing before you study helps you remember that material later, even when the guess is wrong. So there are no lesson gates in the Arena, and a rough first duel is studying, not failing.

St. Hilaire, K. J., Chan, J. C. K., & Ahn, D. (2024). Guessing as a learning intervention: A meta-analytic review of the prequestion effect. Psychonomic Bulletin & Review, 31(2), 411–441.

Why getting it right once isn't enough

Getting a concept right once isn't mastery. Retrieving it correctly in several spaced sessions produced more than a letter-grade improvement on real course exams. That's why concepts you've already answered correctly still come back on later days.

Rawson, K. A., Dunlosky, J., & Sciartelli, S. M. (2013). The power of successive relearning. Educational Psychology Review, 25, 523–548.

Why the Arena sometimes feels hard. That's the point.

The study methods that feel smooth tend to fade fast. The ones that feel effortful tend to stick. Questions you miss now are points you earn on exam day.

Bjork, E. L., & Bjork, R. A. (2011). Making things hard on yourself, but in a good way: Creating desirable difficulties to enhance learning. In Psychology and the Real World (pp. 56–64). Worth Publishers.

What we don't claim

Buddy Arena is designed around this research. We don't promise a pass, a score, or a percentile, and nobody honest can. Leaderboards and streaks are engagement features. They keep you coming back; we make no learning claims for them. Every rationale in the Arena cites its source so you can check us, and this page exists so you can check the design too.

Want to check the questions before you check the citations? The free five-question taste draws from a rotating sampler pool, and each of those questions ships with its answer and rationale on purpose. The explanations are the demo.

Ready when you are. Enter the Arena.