At 08.32 25/02/99 +1300, you wrote:
>Dear All
>
>I was recently conversing with a colleague and the question of why use ORs
>instead RRs came up. My naive response was that the choice seemed to be
>based on the individual's preference and that I had not read anything that
>suggested the use of one was more informative than another (and indeed have
>read some material that suggests ORs are misleading when the OR is high -
>but I don't want to get onto that issue).
>
>Can anyone help me with why odds ratios might be used in preference to
>relative risk or vice versa.

You can read:

Sackett DL, Deeks JJ, Altman DG. Down with odds ratios! Evidence-Based Medicine [EBM Notebook] 1996;2:164-6.
http://www.acponline.org/journals/ebm/sepoct96/downodds.htm

Davies HTO, Crombie IK, Tavakoli M. When can odds ratios mislead? BMJ 1998;316:989-991
http://www.bmj.com/cgi/content/full/316/7136/989

see also related letters

Deeks J. When can odds ratios mislead? Odds ratios should be used only in case-control studies and
logistic regression analyses. BMJ 1998;317:1155-6.
Bracken MB, Sinclair JC. When can odds ratios mislead? Avoidable systematic error in estimating treatment effects must not be tolerated. BMJ 199824;317:1156.
http://www.bmj.com/cgi/content/full/317/7166/1155/a

Altman DG, Deeks JJ, Sackett DL. Odds ratios should be avoided when events are common. BMJ 1998;317:1318
http://www.bmj.com/cgi/content/full/317/7168/1318

Taeger D, Sun Y, Straif K. On the use, misuse and interpretation of odds ratios.
http://www.bmj.com/cgi/eletters/316/7136/989#EL2

Swots corner: What is an odds ratio? Bandolier 1996;25:6
http://www.jr2.ox.ac.uk:80/bandolier/band25/b25-6.html

Bests
Antonino Cartabellotta, MD
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