Conditional Analysis and Unconditional Conclusion in Clinical Trial with Interim Analysis

In a properly defined statistical analysis, the basic requirements include a complete specification of the sample space and a statistical model used in inference. The two are considered as key components for a statistical analysis, if there is any fuzzy description in the key components, the statistical analysis lost its foundation. For a clinical trial with interim analysis, although many techniques to deal with the error inflation caused by the repeated significance tests have been developed, the specifications of the key components were not complete, the clinical trial with interim analysis needs a further refinement.