The Association Between Length of Training and Family Medicine Residents' Clinical Knowledge: A Report From the Length of Training Pilot Study.

Background And Objective: The associations between training length and clinical knowledge are unknown. We compared family medicine in-training examination (ITE) scores among residents who trained in 3- versus 4-year programs and to national averages over time.

Methods: In this prospective case-control study, we compared the ITE scores of 318 consenting residents in 3-year programs to 243 who completed 4 years of training between 2013 through 2019. We obtained scores from the American Board of Family Medicine. The primary analyses involved comparing scores within each academic year according to length of training. We used multivariable linear mixed effects regression models adjusted for covariates. We performed simulation models to predict ITE scores after 4 years of training among residents who underwent only 3 years of training.

Results: At baseline postgraduate year-1 (PGY1), the estimated mean ITE scores were 408.5 for 4-year programs and 386.5 for 3-year programs, a 21.9 point difference (95% CI=10.1-33.8). At PGY2 and PGY3, 4-year programs scored 15.0 points higher and 15.6 points higher, respectively. When extrapolating an estimated mean ITE score for 3-year programs, 4-year programs would still score 29.4 points higher (95% CI=15.0-43.8). Our trend analysis revealed those in 4-year programs had a slightly lesser slope increase compared to 3-year programs in the first 2 years. Their drop-off in ITE scores is less steep in later years, though these differences were not statistically significant.

Conclusions: While we found significantly higher absolute ITE scores in 4 versus 3-year programs, these increases in PGY2, PGY3 and PGY4 may be due to initial differences in PGY1 scores. Additional research is needed to support a decision to change the length of family medicine training.