The second advantage of planning the statistical analysis before the study is an increase in scientific integrity. The
investigators who have a plan ahead of time are less likely to bend the analysis to suit their purpose. A plan also prevents
the process of repeating analyses until something is found that is statistically significant. A post hoc (after the
fact) approach to statistical analysis is inappropriate and increases the chance of making a type I statistical error (see
a future issue of this series on hypothesis testing for a discussion of type I errors).2 If post hoc analyses are used, a
technique such as Bonferroni adjustment is needed to decrease the chance of a type 1 error.2