Clinical / Method Note
SAS-to-R Comparison
Make comparison evidence part of the migration, with the meaning of an acceptable match agreed in advance.
Sources checked
Purpose
Agree what must stay equivalent and what may deliberately change. A PHUSE project report describes comparing migrated R outputs with reference SAS results and reviewing the completed workflow. It supports planning a controlled comparison, not a universal migration result. PHUSE migration report.
What Your Team Reviews
What is the reference?
Agree the specification, input data, output versions and responsible reviewers. Record known limitations in the existing result before using it as a comparison target.
What does a match mean?
Agree identifiers, populations, derivations, missing values, metadata and presentation requirements. SAS and R can represent labels and missing values differently. haven conversion semantics.
How are differences resolved?
Define any numerical tolerance before reviewing results. Separate value differences from formatting differences and explain material exceptions. SAS documentation distinguishes exact and tolerance-based comparisons. SAS comparison concepts.
Outputs to Agree
A migration scope, versioned environment record, comparison report, discrepancy decisions and operating handover. Your programming and statistical reviewers decide whether the scoped outputs are acceptable and what remains unresolved.
Confirm the deliverables and acceptance responsibilities in the engagement scope.
Limits
Matching a reference can reproduce a reference error. Scientific review and appropriate independent checks remain necessary. The R Foundation’s guidance covers the official R distribution and recommended packages; it does not qualify every add-on package or your full deployment. R Foundation guidance.
Sources
- PHUSE: Leveraging AI for Seamless SAS to R Migration: Challenges and Opportunities
EU Connect 2025, ML11, PDF. A conference report by Milena Kraus, Corinna Stöckinger and Robert Bauer, describing one project.
- haven: Conversion Semantics
Official package-author documentation, site version 2.5.5 at review. A reference for data representations, not package qualification.
- SAS: PROC COMPARE Concepts
Archived official documentation, copyright 2010. Confirm behavior in the SAS release selected for the engagement.
- R Foundation: R: Regulatory Compliance and Validation Issues
12 March 2026, PDF. R Foundation guidance, not an FDA-issued document; its scope excludes third-party add-on packages.
Your next step
Agree the comparison scope.
Identify one migration workflow, its reference outputs and the reviewers who will decide acceptance.
Discuss a SAS-to-R Migration Explore Coding Operations