**Objective:** The objective is to develop a checklist for a statistical analysis plan for observational studies that accounts for Initial data analysis and records deviations from initial plans in one document (SAPI). **Scope** of the statistical analysis plans: Observational studies using low dimensional regression type models **Importance:** There is an absence of guidance on incorporating a systematic process for initial data analysis in statistical analysis plans (SAP) or study protocol guidelines. Initial data analysis is often performed, but it may not have been planned or conducted systematically. Revisions of SAPs are often necessary due to unforeseen issues with the data. Such changes should be documented with a rationale in an amended SAP. This protects against ad hoc decisions during analysis, non-transparency, and irreproducibility, even when an SAP was present. This project is being conducted by a committee of members of the **STRATOS Initiative** (Michal Abrahamowicz, Gary Collins, Georg Heinze, Marianne Huebner, Lara Lusa, Willi Sauerbrei, Carsten Schmidt).