Modeling the Public Health Consequences of Raw-Milk Deregulation: Causal Evidence from Staggered Policy Adoption, 1998-2023 Open Access

Abstract

Over the past two decades, many U.S. states have expanded legal access to unpas-

teurized (raw) milk, revealing a broader policy shift toward consumer autonomy in

food markets. This trend raises a central policy question: Does permitting legal

access to raw milk increase population-level risk of food-borne illness? To answer

this question, I construct a novel state-year panel dataset covering 48 U.S. states

from 1998 to 2023, combining detailed legal classifications of raw milk access with

surveillance data from the CDC’s National Outbreak Reporting System. Outcomes

are measured as dairy-associated illnesses, hospitalizations, and outbreaks per 100,000

residents, aggregated into three-year bins. I estimate causal effects using the staggered

Difference-in-Differences framework of Callaway and Sant’Anna (2021) with doubly ro-

bust adjustment. Event-study estimates reveal no evidence of differential pre-treatment

trends. Following legalization, outbreak and hospitalization rates increased by 0.014

and 0.020 cases per 100,000 residents, respectively, both statistically significant at

conventional levels. Illness rates increase by 0.220 per 100,000, but the increase is not

statistically significant. Relative to baseline levels, these rates represent economically

meaningful proportional increases. Overall, the findings show that expanded legal

access to raw milk is associated with measurable increases in adverse public health

outcomes.

Table of Contents

1 Introduction

2 Background and Context

3 Literature Review

4 Data, Variables and Descriptive Statistics

4.1 Data Source

4.2 Key Variables and Sample Construction

4.3 Descriptive Statistics

5 Empirical Strategy

5.1 Treatment Definition

5.2 Identification Strategy

5.3 Estimation

6 Results

6.1 Baseline Outcome Levels in Treated States

6.2 Event-Study Estimates

6.3 Overall Average Treatment Effects on the Treated (ATT)

6.4 Interpreting Treatment Effects in Event Counts

6.5 Economic Interpretation of Treatment Effects

6.6 Summary of Empirical Findings

7 Discussion and Conclusion

7.1 Study Contributions

7.2 Limitations

7.3 Policy Implications

7.4 Conclusion

Appendix

A.1 Framework and Treatment Classification

A.2 Data Construction and Variable Definitions

A.3 Robustness Checks

References

About this Honors Thesis

Rights statement

• Permission granted by the author to include this thesis or dissertation in this repository. All rights reserved by the author. Please contact the author for information regarding the reproduction and use of this thesis or dissertation.

School	Emory College
Department	Economics
Degree	B.A.
Submission	Honors Thesis
Language	English
Research Field	Health Sciences, Public Health Health Sciences, Epidemiology Economics, Agricultural
Keyword	raw milk outbreaks illnesses unpasteurized milk CDC hospitalizations public health
Committee Chair / Thesis Advisor	Dr. Ian McCarthy, Emory University
Committee Members	Dr. Kyungmin (Teddy) Kim, Emory University Dr. Sara Markowitz, Emory University

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