To investigate the effect of duration of clinical training placements in the Northern Territory on rate of return of medical students for an internship in the NT.

Retrospective analysis of medical school and hospital data on all medical students who completed a placement with the Northern Territory Clinical School (NTCS) between 1998 and 2007.

Logistic regression analysis of weeks spent training in the NT against the binary category of return or non-return for an internship in the NT; number of weeks of placement in the NT required for one returning intern for training models with different placement duration and timing.

683 students completed an NTCS placement: short-term Year 4 placements only, 538 (duration, 1–19 weeks, 534; and ≥ 20 weeks, 4); Year 3 40-week placements only, 16; and both Year 3 and Year 4 placements,129 (Year 4 duration, 1–19 weeks, 82; and ≥ 20 weeks, 47). For each student who returned for an NT internship, 122 weeks of placement were required. Placement length was a significant predictor of an NT internship (P < 0.05; odds ratio, 1.08; 95% CI, 1.07–1.09). The most efficient training models (fewest weeks per returning intern) were longer placements (≥ 20 weeks) in Year 4, both for students who also undertook a 40-week Year 3 placement and those who did not (90 and 47 weeks of training per intern, respectively). Students who spent only brief periods in the NT in Year 4 were less likely to return for an internship (P < 0.05).

The rate of return increased with the total length of time spent training in the NT. Short-term Year 4 placements offered the least return for the total number of weeks of placement provided.