---
title: >-
  Using Bounds to Compare the Strength of Exchangeability Assumptions for
  Internal and External Validity
description: >-
  Explore this publication on real-world evidence: Using Bounds to Compare the
  Strength of Exchangeability Assumptions for Internal and External Validity..
date: '2019-01-01'
author: Alexander Breskin
category: Publications
tags:
  - University of North Carolina at Chapel Hill
  - Approval & Commercialization
  - American Journal of Epidemiology
  - 'Yes'
  - Health System Partner
  - Oral Presentation
  - Methods/Pharmacoepi
  - R&D
canonical_url: >-
  https://www.headwaterscience.com/resources/publications/acad-university-of-north-carolina-at-chapel-hill/using-bounds-to-compare-the-strength-of-exchangeability/
source: Headwater Science
license: © 2026 Headwater Science. All rights reserved.
slug: using-bounds-to-compare-the-strength-of-exchangeability
id: 5CO5UCocUEDjbMM1pThPqP
contentType: article
---

## Challenge

Internal validity and external validity require different exchangeability assumptions, but no framework had been developed for formally comparing the strength of these assumptions to guide design choices.

## Solution

Target RWE researchers and UNC collaborators developed and presented a formal framework using bounds to compare the relative strength of exchangeability assumptions for internal versus external validity.

## Impact

Providing a formal bounds framework for comparing internal and external validity assumptions advances Target RWE's methodological capability for designing studies that explicitly address generalizability.

## Use Cases / Links

Exchangeability assumption bounds framework for internal vs. external validity comparison in RWE design, Generalizability assessment methodology for pharma partners demonstrating RWE applicability to label populations