Post hoc ergo propter hoc: some benefits of rationalization

Cum hoc ergo propter hoc ("With this, therefore because of this").

Post Hoc Tests

Familywise Error Familywise error (FWE) is also known as alpha inflation or cumulative Type I error. Familywise error represents the probability that any one of a set of comparisons or significance tests is a Type I error. As more tests are conducted, the likelihood that one or more are significant just due to chance (Type I error) increases. One can estimate familywise error with the following...

Post Hoc Tests

Familywise Error Familywise error (FWE) is also known as alpha inflation or cumulative Type I error. Familywise error represents the probability that any one of a set of comparisons or significance tests is a Type I error. As more tests are conducted, the likelihood that one or more are significant just due to chance (Type I error) increases. One can estimate familywise error with the following...

Post hoc subgroup analysis.

I am surprised by the published conclusions of Hung et al 1 in a recent issue of CHEST (August 2013). The authors’ stated meth ods are not adequate to support their conclusion that hyperimmune IV immunoglobulin (H-IVIG) ben efi ts mortality if given within 5 days to patients with severe 2009 infl uenza A(H1N1) infection. The primary outcome analysis of 34 patients presented in Table 1 of the st...

Post - Hoc Comparisons

The F test used in analysis of variance (ANOVA) is called an omnibus test because it can detect only the presence or the absence of a global effect of the independent variable on the dependent variable. However, in general we want to draw specific conclusions from the results of an experiment. Specific conclusions are derived from focused comparisons which are, mostly, implemented as contrasts ...