ICH E3 section 9.2 calls for discussion of the chosen control and study design, including design problems or biases that may matter for interpretation. This guide concerns the rationale and limitations of the control/design choice; the Study Design guide owns the descriptive overview of the study configuration itself.
ReviewedEvidence1 sourceSectionWriting & Style
Quick answer
Explain why the control group and study design were appropriate for the study and discuss material limitations, bias risks, or design features that affect interpretation.
Key details
Core IssueICH E3 section 9.2 calls for discussion of the chosen control and study design, including design problems or biases that may matter for interpretation.
Registerscholarly, professional, or research/report writing
Important caveats
Scope Boundary
This guide concerns the rationale and limitations of the control/design choice; the Study Design guide owns the descriptive overview of the study configuration itself.
Further guidance
Content
Address the selected control type and other important design features, including safeguards against selection bias when randomization was not used and limitations of designs such as historical controls.
Purpose
Explain why the control group and study design were appropriate for the study and discuss material limitations, bias risks, or design features that affect interpretation.
Sources and evidence
Sources are shown with the role they play in this guide. Historical or style-sensitive claims are kept within the evidence boundary described above.
ICH E3 section 9.4.3 calls for the specific method used to assign patients to treatment groups, including relevant allocation, stratification, or blocking features. This report-body method section is distinct from the detailed randomization scheme and codes placed in appendix 16.1.7 and should not imply randomization when the study used another assignment method.
ICH E3 section 11.4.2.7 identifies special efficacy-analysis considerations for active-control studies intended to support equivalence. This is a CSR efficacy-results reporting issue for active-control equivalence designs; it does not define a universal equivalence margin or replace protocol-level design justification.
ICH E3 section 12.3.3 calls for analysis and discussion across deaths, other serious adverse events, and other significant adverse events after the relevant case listings and narratives. This is an interpretive synthesis, not a duplicate death/serious-event listing or a replacement for individual patient narratives.
ICH E3 section 12.2.3 calls for analysis of adverse events beyond their tabular display, focusing on patterns important to safety interpretation. Do not treat the analysis as a substitute for the event display or patient-level listing, and do not imply causality beyond what the study evidence supports.
ICH E3 section 9.5.2 calls for discussion of the appropriateness, reliability, or relevance of measurements used to assess efficacy and safety when explanation is needed. This subsection justifies or qualifies measurement choices; it does not replace the section that defines the variables, methods, and timing of assessments.
ICH E3 section 12.2.1 calls for a brief summary of adverse events within the safety evaluation before more detailed displays and analyses. Keep this section a high-level summary; it is not a substitute for detailed adverse-event displays, patient-level listings, serious-event treatment, or narratives.
ICH E3 section 9.8 calls for changes made after the study began to the conduct of the study or planned analyses to be described, including timing, reasons, decision process, responsibility, available data, and interpretive implications as applicable. This section is broader than a statistical-methods subsection: it covers material study-conduct changes as well as planned-analysis changes, while detailed statistical methods remain in their dedicated section.
ICH E3 section 12.2.2 provides for structured display of adverse events as part of the clinical study report safety evaluation. A summary display is distinct from patient-level adverse-event listings and from narratives of selected serious or otherwise significant cases.
