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Table 3 Comparison of log-binomial and Robust Poisson methods for analysis of vaso-constriction associated with inspired air*

From: A comparison of two methods for estimating prevalence ratios

Independent Variable Log Prevalence Ratio Estimate (SE) P-Value
  Log-Binomial Robust Poisson Log-Binomial Robust Poisson
Log(Rate) 1.3132 (0.3362) 1.5578 (0.4270) 0.0006 0.0003
Log(Volume) 0.7715 (0.1960) 1.4614 (0.3510) 0.0002 0.0000
  1. * Wald tests were used for the Robust Poisson method, and likelihood ratio tests were used for the log-binomial method. The latter were obtained by fitting a model without the effect being tested. The log-binomial method failed to converge when both independent variables were in the model and when only log(Volume) was in the model. In these cases, the COPY method approximation was used.
  2. The intercept estimate was -1.5147 for the log-binomial method and -1.8311 for the Robust Poisson method. Of the 39 probability estimates, 3 were greater than unity for the Robust Poisson method, and the largest was 1.82.