Apparent drug overdose spike in 2025 driven by flawed modeling
· News-Medical"Many people think CDC drug overdose data are being cooked, but they're not," said Post, director of the Buehler Center for Health Policy and Economics at Northwestern University Feinberg School of Medicine. "We can trust them because they're scientists trying to do the best job they can with difficult circumstances. There was no clear incentive for any administration to inflate these numbers. This was not politics."
What happened?
"That spike made headlines at the time, but it didn't reflect reality," Post said "What we found was a mismatch between predictive models and a rapidly changing epidemic. CDC scientists did the best job they could with fewer people, more constraints and more people watching them."
The study authors emphasize the episode highlights a broader issue: surveillance systems are most vulnerable during turning points, when trends shift direction.
Why it matters
Despite this episode, the researchers stress that federal mortality data remain the most reliable near real-time source for tracking overdose death.
Why the models broke
The overdose crisis has been reshaped by fentanyl, a synthetic opioid that spread unevenly across the country and drove rapid increases in deaths through 2022 and 2023.
Models trained on that explosive growth were later applied to a period of decline. The result:
- Overestimation of deaths in early 2024 and 2025
- False signals of a national "spike"
- Confusion among policymakers, researchers and the public
Looking ahead
The authors call for greater transparency in federal data systems, including advance notice of methodological changes and clear documentation of revisions.
"When the numbers change, people notice," Post said. "We need to make sure they understand why."
More about the study
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