Breslow-Day test A statistical test for the homogeneity of odds ratios. Homogeneity In <javascript:void(0);> systematic reviews homogeneity refers to the degree to which the results of studies included in a review are similar. "Clinical homogeneity" means that, in studies included in a review, the participants, interventions and outcome measures are similar or comparable. Studies are considered "statistically homogeneous" if their results vary no more than might be expected by the play of chance. See <javascript:void(0);> heterogeneity. Odds ratio (OR) The ratio of the odds of an event in the experimental (intervention) group to the odds of an event in the <javascript:void(0);> control group. Odds are the ratio of the number of people in a group with an event to the number without an event. Thus, if a group of 100 people had an <javascript:void(0);> event rate of 0.20, 20 people had the event and 80 did not, and the odds would be 20/80 or 0.25. An odds ratio of one indicates no difference between comparison groups. For undesirable outcomes an OR that is less than one indicates that the intervention was effective in reducing the risk of that outcome. When the event rate is small, odds ratios are very similar to <javascript:void(0);> relative risks. http://www.cochrane.dk/cochrane/handbook/contents.htm Bye, Judit [[alternative HTML version deleted]]
On Tue, 11 Jan 2005 10:45:48 -0500 "Palos, Judit" <PalosJ at bsci.com> wrote:> Breslow-Day test > A statistical test for the homogeneity of odds ratios. >[..some definitions..] Your message was not particularly clear, but if you were looking for R code to do a Breslow-Day test, Google found this for you: http://www.math.montana.edu/~jimrc/classes/stat524/Rcode/breslowday.test.r HTH, Tobias> PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html >
On Wed, 12 Jan 2005, Tobias Verbeke wrote:> On Tue, 11 Jan 2005 10:45:48 -0500 > "Palos, Judit" <PalosJ at bsci.com> wrote: > >> Breslow-Day test >> A statistical test for the homogeneity of odds ratios. >> > [..some definitions..] > > Your message was not particularly clear, but if > you were looking for R code to do a Breslow-Day test, > Google found this for you: >There is code for meta-analyses, including a test of homogeneity that I think is the same as the Breslow-Day one, in the rmeta package. The package does forest plots, too. -thomas