Philip Stark | Searcharxiv

arXiv2025

Does Extending Polling Hours Compensate for Bomb Threats? Evidence from the 2024 Election in Georgia, USA

At least 227~bomb threats against polling places and tabulation centers were received on the day of the 2024 US presidential election. Threats disrupted voting in the swing states of Georgia, Arizona, and Pennsylvania while law enforcement swept polling places. No bombs were found. Roughly a dozen `credible' threats were received in Georgia in DeKalb and Fulton counties, interrupting voting at eleven polling locations; there were dozens of `non-credible' threats in addition. To remediate the effect of the temporary closures of polling places, courts ordered some polling places to remain open late. Nonparametric statistical tests using turnout data from 2020 and 2024 show that this remedy may have been inadequate: in DeKalb, 2024 in-person turnout in precincts closed by threats relative to 2020 turnout in the same precincts was suppressed compared to other DeKalb polling places ($P \approx 0.01$). In Fulton, there is no statistical evidence that in-person voting was suppressed in precincts closed by bomb threats.

physics.soc-ph↗

arXiv2024

Estimating soil carbon sequestration potential and approximating optimal management policies

The impact of a management intervention on the soil organic carbon (SOC) stored in a given volume of soil is moderated by features that determine that soil's sequestration potential under that intervention. To maximize total SOC sequestration cost efficiently, interventions should be targeted to soils with the highest responses and lowest intervention costs. We present a framework for estimating SOC sequestration potentials and approximating efficient management policies. We review relevant sources of measurement uncertainty and formalize policy choice using potential outcomes. An optimal sequestration policy can be approximated by modeling SOC measurements as functions of covariates within each treatment group, using the fitted models to estimate SOC sequestration potential for each plot, and finding the policy that maximizes the average of those estimates. The modeling can use linear regression or other algorithms to learn relationships between features and SOC sequestration potential. We demonstrate this method using data from a study of compost amendments applied to California rangelands. We find that the plots exhibit treatment effects moderated by baseline SOC -- so targeting amendments to plots with lower baseline SOC would increase overall SOC sequestration rates. We evaluate these methods further in simulated field experiments. Refined policy estimates sequestered more SOC than uniform application of the single management policy estimated to have the largest average treatment effect, especially when SOC sequestration potential could be predicted from observed features. We conclude by discussing baseline SOC moderation, observational studies, inference, cost models, and broader policy uncertainties.

stat.AP↗

arXiv2015

End-to-end verifiability

This pamphlet describes end-to-end election verifiability (E2E-V) for a nontechnical audience: election officials, public policymakers, and anyone else interested in secure, transparent, evidence-based electronic elections. This work is part of the Overseas Vote Foundation's End-to-End Verifiable Internet Voting: Specification and Feasibility Assessment Study (E2E VIV Project), funded by the Democracy Fund.

cs.CR↗