Structure and Content of Clinical Study Reports
ICH E3 defines the structure and content of a clinical study report — the single, comprehensive account of an individual clinical trial that integrates the clinical and statistical description, presentation, and analysis into one document acceptable to regulators across the ICH regions. It specifies a numbered 16-section structure covering everything from study objectives and methods through efficacy and safety results to discussion and conclusions, and it lists the appendices, including the protocol, sample case report forms, patient data listings, and statistical documentation. A 2012 questions-and-answers document clarified aspects of scope without changing the core structure.
What this does not cover
stated in the document's own scope- It does not govern how a trial is conducted; the good-clinical-practice requirements are in ICH E6.
- It does not define the statistical methodology or estimands, which are the subject of ICH E9.
- It does not cover the integrated summaries of safety and efficacy submitted across a programme; those follow the Common Technical Document structure.
- It is a reporting standard for an individual study, not a template for periodic post-marketing safety reports.
Always verify against the current published text before relying on it for a submission or inspection.
Overview
ICH E3 gives clinical trials a common reporting language. Before it, the same study could be written up in different ways for different regulators; E3 established one core report, structured identically across the ICH regions, that combines the clinical narrative and the statistical analysis. The guideline sets a 16-section skeleton — from introduction and objectives, through methods and results for efficacy and safety, to discussion and conclusions — and defines the appendices that accompany it, such as the protocol, sample case report forms, and patient data listings. The result is a document a reviewer in any region can read and assess efficiently.
Legal basis & how it acquires force
E3 is a harmonised guideline, effective through adoption in each ICH region rather than as law on its own. The FDA issued it as guidance for industry in 1996 and the EMA adopted it as a CHMP scientific guideline. The clinical study reports it structures form part of the clinical documentation in a marketing application assessed under each region's medicines legislation. The report describes trials conducted under the good-clinical-practice requirements of ICH E6, and it presents the analyses framed by ICH E9.
Document structure
| Part | Covers |
|---|---|
| Synopsis and introduction | Short standalone summary of the study plus background and objectives |
| Investigational plan | Study design, selection of subjects, treatments, endpoints, and the statistical methods planned |
| Study patients | Disposition, protocol deviations, and analysis populations |
| Efficacy and safety results | Analysis of efficacy endpoints and the safety evaluation, including adverse events and laboratory findings |
| Discussion and conclusions | Interpretation of efficacy and safety and the overall conclusions |
| Appendices | Protocol and amendments, sample case report form, patient data listings, and statistical documentation |
Key requirements
- Report each study in the numbered 16-section structure so reviewers can navigate consistently across submissions.
- Integrate the clinical and statistical descriptions into a single core report rather than separate documents.
- Describe the study objectives, design, and methodology in enough detail to allow the analysis to be understood and reproduced.
- Present efficacy and safety results with the pre-specified analyses, including disposition, demographics, and protocol deviations.
- Include the required appendices: protocol and amendments, sample case report form, and statistical and patient-level documentation.
- Provide individual patient data listings and analysis documentation to support the reported results.
- Discuss and interpret the findings, stating conclusions supported by the data.
Implementation tips
- Map the statistical analysis plan onto the E3 results sections before writing, so tables and text follow one structure.
- Assemble appendices in parallel with the report body — late protocol-amendment and case-report-form collation is a common bottleneck.
- Reconcile disposition, demographics, and deviation counts across the report and its listings before finalising.
- Write the synopsis to stand alone, since it is often read before the full report.
International alignment
E3 applies across the EU, Japan, and the United States, and its section structure has become the de facto template for clinical study reports worldwide, including for many non-ICH regulators. It works with ICH E6, which governs the conduct of the trial being reported, and ICH E9, whose analyses and — since 2019 — estimands are presented in the report. A 2012 ICH questions-and-answers document addressed common queries on applying E3.
ICH E3: frequently asked questions
Quick answers to common questions about ICH E3.
How many sections does an ICH E3 report have?
The core report follows a numbered 16-section structure, supported by a set of defined appendices.
Is the clinical study report one document or two?
One. E3's central idea is a single core report that integrates the clinical and statistical description, presentation, and analysis of the study.
What appendices does E3 require?
Appendices include the study protocol and amendments, a sample case report form, patient data listings, and statistical documentation supporting the analyses.
Did E3 change after 1995?
The guideline reached Step 4 on 30 November 1995. A 2012 questions-and-answers document clarified scope, but the 16-section structure was not replaced.