Skip to content


  • Erratum
  • Open Access

Erratum to: A simple method for analyzing data from a randomized trial with a missing binary outcome

BMC Medical Research Methodology20044:1

  • Received: 02 January 2004
  • Accepted: 07 January 2004
  • Published:

The original article was published in BMC Medical Research Methodology 2003 3:8

In this article [1], equation (8) is incorrect because it omitted the covariance terms. Let h denote the number of strata, so s = 1,2,...,h. Let T denote transpose, • denote matrix product, and Diagonal Matrix [vector] denote a matrix of all 0's except for vector on the diagonal. The correct formula is


In our example, the effect of the correction was negligible; the corrected estimated standard error was the same to two significant digits as the incorrect value.

Also for clarification, we note that in the sentence after (11), it is an assumption that, within stratum s, the difference, Δ s , does not depend on the unobserved covariate x.


Authors’ Affiliations

Biometry Research Group, Division of Cancer Prevention, National Cancer Institute, USA
Department of Mathematics, Statistics, and Computer Science, Bar Ilan University, Ramat Gan, 52900, Israel


  1. Baker SG, Freedman LS: A simple method for analyzing data from a randomized trial with a missing binary outcome. BMC Medical Research Methodology. 2003, 3: 8-10.1186/1471-2288-3-8.View ArticlePubMedPubMed CentralGoogle Scholar
  2. Pre-publication history

    1. The pre-publication history for this paper can be accessed here:


© Baker and Freedman; licensee BioMed Central Ltd. 2004

This article is published under license to BioMed Central Ltd. This is an Open Access article: verbatim copying and redistribution of this article are permitted in all media for any purpose, provided this notice is preserved along with the article's original URL.