Writing & StyleStyle guide

Split Study Dataset Files in eCTD

FDA’s June 2026 conformance guide states that datasets greater than 5 GB should be split into smaller datasets no larger than 5 GB for submission and placed in a separate split subdirectory, with the split explained in the relevant reviewer guide. The 5 GB threshold and directory handling are current FDA technical-conformance instructions and may change; do not generalize them to other regulators or future specifications without rechecking the current guide.

Quick answer

When a study dataset exceeds the current FDA processing threshold described by the guide, provide the smaller split datasets in the designated split subdirectory and explain how they were split in the relevant reviewer guide.

Key details

Core IssueFDA’s June 2026 conformance guide states that datasets greater than 5 GB should be split into smaller datasets no larger than 5 GB for submission and placed in a separate split subdirectory, with the split explained in the relevant reviewer guide.
Registerscholarly, professional, or research/report writing

Important caveats

Scope Boundary

The 5 GB threshold and directory handling are current FDA technical-conformance instructions and may change; do not generalize them to other regulators or future specifications without rechecking the current guide.

Further guidance

Content

Retain the larger non-split dataset as directed by the current guidance and reduce character-variable lengths before splitting when that guidance applies.

Purpose

When a study dataset exceeds the current FDA processing threshold described by the guide, provide the smaller split datasets in the designated split subdirectory and explain how they were split in the relevant reviewer guide.

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.

  1. Study Data Technical Conformance Guide - Technical Specifications Document (opens in a new tab)U.S. Food and Drug Administration · Current FDA technical specifications for standardized clinical and nonclinical study-data submissions, including reviewer guides, datasets and eCTD organization.

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