Table 1 Functional forms under comparison
From: Assessment of learning curves in complex surgical interventions: a consecutive case-series study
|  | g(x ij ;θ) | θ | Model constraints |
|---|---|---|---|
Linear | β x ij | (β) | β≤0 |
Logarithmic | βlog(x ij +1) | (β) | β≤0 |
Power | β(x ij +1)−γ | (β,γ) | β≥0, γ>0, α≠0 |
Exponential | βexp(−γ x ij ) | (β,γ) | β≥0, γ>0, α≠0 |