Numerical Experiment: Bias and Variance of KL Estimators
q = N(0,1), p = N(0.10, 1), True KL = μ²/2 = 0.00500
| Estimator | E[k] | Bias / True KL | Std / True KL | Verdict |
| k₁ = −log r | — | — | — | — |
| k₂ = ½(log r)² | — | — | — | — |
| k₃ = (r−1)−log r | — | — | — | — |
q = N(0,1), p = N(μp, 1). True KL = μ²/2. Samples x ~ q; log r = μx − μ²/2. Drag μ to see how bias and variance change — notice k₃ stays unbiased everywhere while k₂'s bias grows with μ.