Luke Maddock

Economics PhD Candidate, Colorado State University

Manuscripts in Submission

  1. Petach, L., Maddock, L., & Pena, A.-A. Housing Affordability and Homelessness: Evidence from Commuting Zones. Revise and Resubmit at Economic Development Quarterly.

  2. Maddock, L., McKee, S., Nelson, F., & Altringer, L. Valuation of Wetland Ecosystem Services in the United States. Submitted to Ecosystem Services.
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  3. Maddock, L. & Pena, A.-A. Funding, Facilities, and the Face of Homelessness: Heterogeneous Impacts of Federal Grants on Sheltered and Unsheltered Counts. Revise and Resubmit at Southern Economic Journal.
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Working Papers

  1. Maddock, L. Voucher Tenant Mobility and Rental Market Dynamics: Evidence from Source of Income Protection Laws. (Job Market Paper).
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    Abstract

    I study how source-of-income (SOI) protections affect where voucher households live and rents in the segments where vouchers transact. I assemble an annual panel of incorporated places with at least 65,000 residents from 2011–2019 and exploit staggered adoption across 57 jurisdictions (first effective dates 2013–2018). Identification follows Callaway & Sant’Anna with doubly-robust adjustment using 2012 baseline covariates and never-adopters as the counterfactual. Across four measures of voucher household geographic concentration, event-study profiles show flat pre-trends and no detectable post-adoption change. By contrast, lower-tier rents rise after adoption: the 25th-percentile contract rent increases by 0.049 log points (about 5%), the 75th percentile is unchanged, and the stock share affordable at less than 30% of HAMFI falls by 1.8 percentage points. Effects are larger under stronger laws (greater enforcement, fewer exemptions) and in tighter rental markets (lower baseline vacancy). Results are robust to a synthetic staggered DiD estimator and to allowing one year of anticipation. The pattern is consistent with pass-through of compliance and screening costs in voucher-relevant segments without re-sorting of voucher households within places. Legal access alone appears insufficient to generate neighborhood gains absent reduced leasing frictions and expanded low-rent supply.

  2. Maddock, L., McKee, S., Altringer, L. Total Economic Valuation of Inland Wetlands in the United States: A Machine Learning Approach.

    Abstract

    Wetlands provide critical ecosystem services including flood regulation, water purification, and carbon storage, yet over one-third of global wetland area has been lost since 1970, while states lack consistent, spatially explicit valuations to inform conservation decisions. This paper develops the first national-scale framework for valuing inland wetland ecosystem services across all fifty states using machine learning-based benefit transfer. We implement a three-stage methodology: (1) stratified random sampling of National Wetlands Inventory polygons by Environmental Protection Agency Level III ecoregion, wetland type, and size class; (2) extraction of comprehensive ecological and socioeconomic covariates from wetland footprints and extended 50-km buffers, including climate trends, land-cover composition, human modification indices, soil properties, and species richness; and (3) training supervised machine learning models on the Ecosystem Service Valuation Database to predict per-hectare values while avoiding double-counting through rigorous classification of final versus intermediate services. Our framework generates the first fifty-state estimates of wetland ecosystem value at consistent resolution, demonstrating improved predictive accuracy and better capture of local heterogeneity compared to traditional transfer methods. These results provide states and federal agencies with a rigorous, transparent foundation for wetland conservation prioritization, mitigation banking, and ecosystem service accounting, while advancing the field by demonstrating how machine learning can enhance benefit transfer with scientific rigor.

  3. Gifford, T. & Maddock, L. The Mental and Physical Health Effects of Legalized Sports Betting in the United States.

    Abstract

    Following the Supreme Court's 2018 decision striking down the Professional and Amateur Sports Protection Act, mobile sports betting has rapidly expanded across the United States, with Americans wagering $121 billion in 2023 alone and industry revenue reaching $11 billion. Despite this explosive growth and mounting evidence of gambling-related financial harms, research on broader health and social consequences remains limited. This paper examines the causal effects of mobile sports betting legalization on physical and mental health outcomes using the staggered rollout of state legislation between 2018-2022. We employ the Callaway and Sant'Anna (2021) difference-in-differences estimator to analyze data from the Behavioral Risk Factor Surveillance System and American Community Survey, capturing health indicators, substance use patterns, and health insurance coverage across treated and control states. Our methodology accounts for time-heterogeneous treatment adoption and estimates group-time average treatment effects to assess both immediate and cumulative exposure impacts. Preliminary findings suggest significant associations between mobile betting legalization and several health outcomes, including increased substance use (tobacco) and worsened mental health indicators, though effects are attenuated when examining population-wide averages that include non-gamblers. The results contribute to growing evidence of sports betting's broader social costs beyond documented financial harms, informing ongoing policy debates about gambling regulation and public health protection in an era of rapid industry expansion.

Presentations

  1. Maddock, L., McKee, S., Altringer, L. Total Economic Valuation of Inland Wetlands in the United States: A Machine Learning Approach. Wildlife Damage Management Conference. (03/25)

  2. Maddock, L., McKee, S., Nelson, F., Altringer, L. Economic Valuation of Wetland Ecosystem Services in the United States: A Machine Learning Approach. Panel Presentation, Eastern Economics Association, New York City, NY (02/25)

  3. Maddock, L. Source of Income Discrimination and Homelessness: Effects of Anti-Discrimination Laws. Panel Presentation, Southern Economics Association, Washington DC (11/24)

  4. Maddock, L. & Pena, A-A. Funding, Facilities, and the Face of Homelessness: Heterogeneous Impacts of Federal Grants on Sheltered and Unsheltered Counts. Panel Presentation, Midwestern Economics Association Conference, Cleveland, OH (04/23)