1. What is the Statistical Analysis Plan (SAP)?

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Several clinical trial documents are prepared to support the trial design, data collection, analysis and reporting. The statistical analysis plan (SAP) is one of these documents. The SAP provides details on the scope of planned analyses, population definitions and methodology. The SAP is crucial for guiding the data analyses and should therefore be created prior to such data analyses. The SAP is often integrated in the study protocol and must be submitted with the clinical trial application before the trial begins.

The SAP is submitted to Regulatory Authorities also as part of the submission package. The SAP is also an appendix of the clinical study report. The SAP is stored in the trial master file and it is used during audits to check if statistical analyses are performed as planned. The role of the SAP is explained in the International Council for Harmonisation (ICH) E9 guideline 'Statistical principles for clinical trials'.

For each trial, one must specify upfront the planned statistical analysis in the SAP. This should include:

  • Primary and secondary endpoints.
  • Analysis methods.
  • Primary) analysis set.
  • Pre-defined comparisons and significance levels.
  • Exploratory analyses.
  • Trial maturity.
Below, we give an explanation and some examples for all of these categories.