Table 8.
Comparison of prevalence ratios and respective confidence interval estimates (obtained by unadjusted Poisson/Cox regression, Poisson regression with scale factor adjusted by χ2 and deviance, Poisson/Cox regression with robust variances, log-binomial regression and logistic regression) and odds ratio with confidence interval estimate (obtained by logistic regression) with the Mantel-Haenszel prevalence ratio in the analysis of the original and modified data using asthma as the outcome, maternal smoking as the risk factor and social class as confounder (situation 2).
| Original data | Point estimate | 95% Confidence interval | ||||
| value | % diff. | lower | upper | width | % diff. | |
| PR Mantel-Haenszel | 1.22 | -- | 1.03 | 1.45 | 0.41 | -- |
| PR Poisson/Cox (unadj) | 1.22 | 0.0% | 0.99 | 1.51 | 0.51 | 23.9% |
| PR Poisson (χ2) | 1.22 | 0.0% | 1.03 | 1.45 | 0.42 | 2.7% |
| PR Poisson (deviance) | 1.22 | 0.0% | 1.03 | 1.46 | 0.43 | 3.9% |
| PR Poisson/Cox (robust) | 1.22 | 0.0% | 1.03 | 1.45 | 0.41 | -0.2% |
| PR log-binomial | 1.23 | 0.1% | 1.04 | 1.45 | 0.41 | -0.4% |
| OR logistic regression | 1.36 | 11.0% | 1.05 | 1.76 | 0.71 | 70.9% |
| Modified data | Point estimate | 95% Confidence interval | ||||
| value | % diff. | lower | upper | width | % diff. | |
| PR Mantel-Haenszel | 1.62 | -- | 1.41 | 1.87 | 0.47 | -- |
| PR Poisson/Cox (unadj) | 1.62 | -0.4% | 1.33 | 1.96 | 0.63 | 36.0% |
| PR Poisson (χ2) | 1.62 | -0.4% | 1.38 | 1.90 | 0.52 | 10.9% |
| PR Poisson (deviance) | 1.62 | -0.4% | 1.39 | 1.88 | 0.49 | 4.3% |
| PR Poisson/Cox (robust) | 1.62 | -0.4% | 1.40 | 1.86 | 0.46 | -2.0% |
| PR log-binomial | 1.65 | 1.7% | 1.44 | 1.90 | 0.46 | -1.5% |
| OR logistic regression | 2.49 | 53.5% | 1.90 | 3.27 | 1.37 | 193.1% |