Rationale: Medical students have few validated predictors of USMLE performance. We hypothesized that USMLERx Step 1 Qmax could predict USMLE Step 1 performance.

Methods: In this prospective cohort study, 26 U.S. medical students who used USMLERx for USMLE preparation completed baseline questionnaires regarding their performance on USMLERx, Kaplan Qbank and the Medical College Admissions Test (MCAT). All questionnaires were completed within one week of participants taking their USMLE examination. Participants subsequently reported their 3-digit USMLE Step 1 scores when they became available. Spearman’s rho and single linear regression modeling were used to assess associations between variables.

Results: See table below. Participants had higher than average scores for the USMLE Step 1, MCAT, and USMLERx. USMLERx scores strongly correlated with USMLE scores. Kaplan and MCAT scores had moderate correlation. In single linear regression modeling, USMLERx, Kaplan Qbank and MCAT scores were highly significant predictors of USMLE performance with high T-scores. USMLERx scores were able to account almost 80% of the variance in USMLE scores.

Test	Mean score (SD)	Correlation (Rho)	T-score	p-value	Variance (R2)
USMLERx	68.9 ±7.7	0.89	7.95	<.001	0.79
Kaplan	67.6±7.2	0.76	5.17	<.001	0.67
MCAT	31.7 ±0.5	0.73	4.80	<.001	0.59
USMLE (3-digit)	234.7 ±19.8	–	–	–	-

 

Conclusions: USMLERx, Kaplan and MCAT scores appear to be significant predictors of USMLE performance. In this sample, USMLERx was highly correlated with the USMLE Step 1 performance and was able to predict approximately 80% of the variation in USMLE scores.

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You can also use the following formula:
USMLERx(%)*2.64 + 47 = USMLE 3-digit score (+/- 20 for the 95% CI)