Introduction

In computing and programming, a diff is a useful tool to show changes between two versions of a file. It pinpoints exact positions where changes occur. Changes can be of additions, deletions, and modifications. CDISC sees similar applications for standards and introduces a diff feature through CDISC Library. In this application, a diff is a metadata comparison that computes and displays the differences in normative contents between 2 versions of a standard. Highlights from this feature:

• Machine-readable format is accessible through the API.
• Diff reports are downloadable from Data Standards Browser as an Excel spreadsheet. Refer to Data Standards Browser for instructions.
• Diff report has color coding to visually indicate how a value changes before & after.
• Diff works for all standards: CDASH, SDTM, SEND, ADaM, and CT.
• Comparison can be made against 2 successive versions (e.g., adamig-1-2 against adamig-1-1), or skipped versions (e.g., sdtmig-3-3 against sdtmig-3-1-2).

Basic Construct

For comparing a product to its immediate version predecessor, the basic construct of a diff API request is: /mdr/diff/{product}/{version}

For comparing to an arbitrary version, /mdr/diff/{product}/{version}/{previous}

Examples