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Specific guide to this web site for:

 1.  Medical School
      Educators 
      in Statistics

 2.  Medical Students

 3.  Science media writers

 4.  High School & College
     Statistic Teachers

   Misadventures:

1. Harvard led MI study

2. JACC study 
   (J. of Amer. Coll.
   Cardio.)

3. NEJM cath study

4. Amer. J. of Cardio.
    review of literature

5. ALLHAT
    controversy 

6. Oat bran study

7. Pregnancy & Alcohol

8. Are Geminis really
    different?
      
9. Columbia 'Miracle' Study  
                                                 

Additional Topics:

Celebrex

Limitations of Meta-Analyses

Large Randomized Clinical Trials

Tale of Two Large
Trials

Advocate meta-analyses

Network meta-analyses

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The tendency to perform inappropriate subgroup analysis which leads to incorrect conclusions will be alive and well in the medical literature 10 years from now. 

There can be an almost irresistible urge for investigators of a medical trial with a negative outcome to subdivide the data in a way to find a positive outcome for some subgroup. Similarly, if the authors have any other preconceived opinions, the data is often subdivided to see if that opinion can be supported in some fashion by subgroup analysis. 

It is not that the trial leaders want to come up with something false. Frequently a trial is performed regarding a treatment for which there is a great deal of optimism. The investigators do not want to miss some positive aspect of the treatment. In addition appropriate subgroup analysis can reveal important information.

Unfortunately, excessively subdividing the trial, particularly in ways that were not planned prior to the trial results were known, will often lead to conclusions that are subsequently shown to be incorrect. 

The best hope for decreasing the number of inappropriate and erroneous conclusions resulting from excessive subgroup analysis is a rigorous editorial policy by the major medical journals. The journals through their review process, which occurs prior to publication of an article, provide the best opportunity to decrease the frequency of conclusions derived from inappropriate and excessive subgroup analysis.

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