A comparison of two methods for estimating prevalence ratios

Details

• Alternative Title:
  BMC Med Res Methodol
• Personal Author:
  Petersen, Martin R ; Deddens, James A
• Description:
  Background
  
  It is usually preferable to model and estimate prevalence ratios instead of odds ratios in cross-sectional studies when diseases or injuries are not rare. Problems with existing methods of modeling prevalence ratios include lack of convergence, overestimated standard errors, and extrapolation of simple univariate formulas to multivariable models. We compare two of the newer methods using simulated data and real data from SAS online examples.
  
  Methods
  
  The Robust Poisson method, which uses the Poisson distribution and a sandwich variance estimator, is compared to the log-binomial method, which uses the binomial distribution to obtain maximum likelihood estimates, using computer simulations and real data.
  
  Results
  
  For very high prevalences and moderate sample size, the Robust Poisson method yields less biased estimates of the prevalence ratios than the log-binomial method. However, for moderate prevalences and moderate sample size, the log-binomial method yields slightly less biased estimates than the Robust Poisson method. In nearly all cases, the log-binomial method yielded slightly higher power and smaller standard errors than the Robust Poisson method.
  
  Conclusion
  
  Although the Robust Poisson often gives reasonable estimates of the prevalence ratio and is very easy to use, the log-binomial method results in less bias in most common situations, and because it fits the correct model and obtains maximum likelihood estimates, it generally results in slightly higher power, smaller standard errors, and, unlike the Robust Poisson, it always yields estimated prevalences between zero and one.
  
  
• Subjects:
  Analysis Of Variance Computer Simulation Cross-Sectional Studies Likelihood Functions Logistic Models Models, Statistical Poisson Distribution Prevalence
• Source:
  BMC Med Res Methodol. 2008; 8:9.
• Document Type:
  Journal Article
• Volume:
  8
• Collection(s):
  CDC Public Access
• Main Document Checksum:
  urn:sha256:d1295b844e7cbb8979df31352a7b7079ac2a91bef234fd91edb97b1cb1e19167
• Download URL:
  https://stacks.cdc.gov/view/cdc/3380/cdc_3380_DS1.pdf
• File Type:
  [PDF - 259.00 KB ]