Table 1. Comparison of HIV Incidence Estimators For 3-State Model in Figure 1 1.
| Incidence Rate | sens | spec (spec1, spec2) | Estimator (eq. #) | Expected Value2 | Standard Error2 | Expected CI Width |
|---|---|---|---|---|---|---|
|
| ||||||
| Incidence Rate sens | (spec1, spec2) | spec Estimator (eq. #) | Value2 | Expected Error2 | Standard Width | Expected CI |
| 2% | 68.1% | 96.9% | Unadjusted (1) | 2.0% | 0.39% | ±0.77% |
| (76.7%, 99.1%) | Adjusted: | |||||
| known sens/spec (2) | 2.0% | 0.58% | ±1.14% | |||
| estd.3 sens/spec (7) | 2.0% | 0.75% | ±1.46% | |||
| known sens/spec1/spec2 (4) | 2.0% | 0.43% | ±0.85% | |||
| estd.3 sens/spec1/spec2 (8) | 2.0% | 0.45% | ±0.88% | |||
| 4% | 68.2% | 93.1% | Unadjusted (1) | 4.0% | 0.56% | ±1.10% |
| (76.7%, 97.7%) | Adjusted: | |||||
| known sens/spec (2) | 4.0% | 0.86% | ±1.69% | |||
| estd.3 sens/spec (7) | 4.0% | 1.07% | ±2.11% | |||
| known sens/spec1/spec2 (4) | 4.0% | 0.63% | ±1.24% | |||
| estd.3 sens/spec1/spec2 (8) | 4.0% | 0.68% | ±1.33% | |||
| 8% | 67.6% | 81.9% | Unadjusted (1) | 8.0% | 0.79% | ±1.55% |
| (76.6%, 89.4%) | Adjusted, | |||||
| known sens/spec (2) | 8.0% | 1.35% | ±2.64% | |||
| estd.3 sens/spec (7) | 8.0% | 1.51% | ±2.95% | |||
| known sens/spec1/spec2 (4) | 8.1% | 1.02% | ±2.00% | |||
| estd.3 sens/spec1/spec2 (8) | 8.1% | 1.08% | ±2.12% | |||
1
Based on a cross-sectional sample of size N = 3000 from a population with 10% prevalence and window period with mean of 0.5 years and standard deviation of 0.6 years.
2
Estimated by 2000 simulated studies. Estimated incidence taken to be 0 for simulations in which numerator of adjusted estimator is negative.
3
Estimated sensitivity and specificity are drawn from a normal distribution with standard errors of 2%, symmetrically truncated with an upper limit of 1. For example, if specificity is drawn from a normal distribution with mean 97.5%, values that are greater than 1 or less than 95% are discarded.