Figure 2.
Institutional risk-adjusted cumulative sum (Cusum). Left, Unadjusted Cusum shows that an unacceptable threshold (red lines) was crossed at 32 cases (indicated by *), and only acceptable thresholds (gray lines) are crossed in subsequent cases, indicating proficient performance beyond 32 cases. Right, Risk-adjusted Cusum shows an unacceptable threshold crossed at 22 cases (indicated by *) with subsequent proficiency.