Evidence mapPaperPMID 40217180Full record

ArticleBMC public health2025

An application of the augmented synthetic control method within a target trial framework: the case of the soda tax policy in California.

Fan Zhao, Risha Gidwani, May C Wang, Liwei Chen, Roch A Nianogo

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In one paragraph

Article in BMC public health, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 2 papers.

0numbers the graph read from it
0cells of the map it votes in
2citing papers in PubMed
field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

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Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

2 citing papers in PubMed.

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4 · The record

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5 · Who and what money

Authors and funding

5 authors.

Fan ZhaoDepartment of Epidemiology, Fielding School of Public Health, University of California, Los Angeles (UCLA), Los Angeles, CA, USA. zhaofan1996@g.ucla.edu.
Risha GidwaniDepartment of Health Policy and Management, Fielding School of Public Health, University of California, Los Angeles (UCLA), Los Angeles, CA, USA.
May C WangDepartment of Community Health Science, Fielding School of Public Health, University of California, Los Angeles (UCLA), Los Angeles, CA, USA.
Liwei ChenDepartment of Epidemiology, Fielding School of Public Health, University of California, Los Angeles (UCLA), Los Angeles, CA, USA.
Roch A NianogoDepartment of Epidemiology, Fielding School of Public Health, University of California, Los Angeles (UCLA), Los Angeles, CA, USA.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

backgroundSugar-sweetened beverage (SSB) consumption is associated with increased obesity risk. One microeconomic intervention approach that has been studied is the increase of the cost of SSBs through SSB taxes. This study aims to apply the augmented synthetic control method (ASCM) within a target trial framework to estimate the impact of a 1-cent-per-ounce SSB tax on obesity prevalence in California.

methodsWe used 2012-2020 data from the California Health Interview Survey (CHIS)'s AskCHIS Neighborhood Edition (AskCHIS NE) and the American Community Survey (ACS). The outcome of interest was obesity prevalence at the city level for people aged 18 and older. The estimated effect of the policy was calculated as the difference between the observed outcome in each soda tax city in the post-policy period and the predicted outcome in the synthetic controls in the post-policy period. The causal estimand of interest was the average treatment effect among the treated (ATT). We adjusted for sex, age, employment status, education, race/ethnicity, marital status, poverty, household median income, population size, and percentage of people who took public transportation to work.

resultsRelative to not implementing a soda tax, the mean difference in obesity prevalence three years after the implementation of a soda tax was -5.5 (95%CI -34.9 to 21.1) percentage points (pp) in Berkeley, -1.7 (95%CI, -11.3 to 6.8) pp in Albany, -1.0 (95%CI, -6.5 to 4.3) pp in Oakland, and 2.6 (-11.0 to 16.8) pp in San Francisco. Overall, the mean difference in obesity prevalence was -1.4 (95%CI, -9.2 to 5.7) pp.

conclusionsIn this study, we illustrated the use of the augmented synthetic control methodology within a target trial framework with group-level longitudinal data. Our estimates of the impact of SSB tax policy on the obesity prevalence in California were imprecise.

Indexed as

Carbonated BeveragesObesitySugar-Sweetened BeveragesTaxesAdolescentAdultAgedCaliforniaFemaleHealth SurveysHumansMaleMiddle AgedPrevalenceYoung AdultAugmented synthetic controlCaliforniaObesitySSB taxTrial emulation framework

Identifiers

PMID40217180
PMCPMC11987390

What Socratic holds

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the Socratic graph.