Research
Click here for my Research Gate profile and here for Google scholar.
Grants
Active Grants
National Institutes of Health, National Institute of Drug Abuse, Proposal R01DA052214, "Spatio-temporal Methods for Surveillance of the Opioid Syndemic" Role: MPI (with David Kline - WFUHS).
Los Alamos National Laboratory, Laboratory Directed Research & Development grant, Project 20220209ER, “Assessing Environmental and Health Impacts of Airborne Particulates,” 10/1/2021 - 9/30/2024, Role: co-I (PI Kimberly Kaufeld - LANL).
National Science Foundation, Computational & Data-Enabled Science and Engineering in Mathematical and Statistical Sciences, Proposal 2151881, “Scalable Models, Fast Computation and Predictability for Ordinal Spatio-temporal Data,” 7/1/2022 - 6/30/2025, Role: co-PI (PI Rob Erhardt - WFU).
Completed Grants
National Institutes of Health, National Institute of Drug Abuse R21DA045236, "A Bayesian Spatio-temporal Approach for Estimating County-Level Opioid Misuse Rates in Ohio," 2018 - 2021.
Publications
Submitted Papers
Lotspeich, S., Mullan, A.E., D’Agostino McGowan, L., Hepler, S.A. Combining straight-line and map-based distances to investigate the connection between proximity to healthy foods and disease.
Kline, D.M., White, B.N., Lancaster, K.E., Egan, K.L., Murphy, E., Miller, W.C., Hepler, S.A. Estimating prevalence of opioid misuse in North Carolina counties from 2016-2021: An integrated abundance model approach.
Murphy, E., Kline, D., Egan, K.L., Lancaster, K.E., Miller, W.C., Waller, L., Hepler, S.A. Understanding the Opioid Syndemic in North Carolina: A Novel Approach to Modeling and Identifying Factors.
Santaella-Tenorio, J., Rivera-Aguirre, A. Hepler, S.A., Kline, D., Cantor, J., DeYoreo, M., Martins, S.S., Krawczyk, N., Cerda, M. Access to medications for opioid use disorder and overdose trajectories during the early synthetic opioid crisis: a county-level analysis in New York State during 2010-2018.
Erhardt, R., Hepler, S.A., Wolodkin, D.*, Greene, A.+, "Spatio-Temporal Forecasting for the U.S. Drought Monitor."
Kline, D., Hepler, S.A., Krawczyk, N., Waller, L., Cerda, M., "A multivariate multiple change point model to describe opioid overdose deaths across the United States."
Published and Accepted Papers
Hepler, S.A., Yang, B.* (2024+) Occupancy Models with Autocorrelated Detection Heterogeneity. Environmental and Ecological Statistics. In Press.
Erhardt, R., Di Vittorio, C., Hepler, S.A., Lowman, L.E.L., Wei, W+. (2024+) Homogenized Gridded Dataset for Drought and Hydrometeorological Modeling for the Continental United States. Scientific Data. In Press.
D'Agostino McGowan, L., Lotspeich, S.C., Hepler, S.A. (2024+) The `Why' behind including `Y' in your imputation model. Statistical Methods in Medical Research. In Press.
Hepler, S.A., Kaufeld, K.K., Kline, D., Greene, A., Gorris, M.E. (2024+) Estimating Coccidioidomycosis Endemicity While Accounting for Imperfect Detection Using Spatio-temporal Occupancy Models. American Journal of Epidemiology. In Press.
Anderson, T.M., Hepler, S.A., Holdo, R., Donaldson, J., Erhardt, R., Hopcraft, G., Hutchinson, M., Huebner, S., Morrison, T., Muday, J., Munuo, I., Palmer, M., Pansu, J., Pringle, R., Sketch, R.+, Packer, C., (2024) Interplay of competition and facilitation in grazing succession by migrant Serengeti herbivores. \textit{Science}. 383.6684: 782-788.
Estadt, A.T., White, B.N., Ricks, J., Lancaster, K.E., Hepler, S.A., Miller, W.C., Kline, D. (2024) The impact of fentanyl on state and county-level psychostimulant and cocaine overdose death rates by race in Ohio from 2010-2020; a time series and spatio-temporal analysis. Harm Reduction Journal. 21(13). (Link).
Hepler, S.A, Erhardt, R. (2024+) multiocc: An R package for spatio-temporal occupancy models for multiple species. The R Journal. In Press.
Santaella-Tenorio, J., Hepler, S.A. (co-first author), Kline, D., Rivera, A., Cerda, M. (2024+) Estimation of opioid misuse prevalence in New York State counties, 2007-2018. A Bayesian spatio-temporal abundance model approach. American Journal of Epidemiology. In Press.
Kwon, J.*, Kline, D., Hepler, S.A., (2023) A Spatio-temporal Hierarchical Model to Account for Temporal Misalignment in American Community Survey Explanatory Variables. Spatial and Spatio-temporal Epidemiology, 46(100593). (Link).
Dong, Q.*, Kline, D., Hepler, S.A., (2023) A Bayesian Spatio-temporal Model to Optimize Allocation of Buprenorphine in North Carolina. Statistics and Public Policy, 10(1). (Link).
Kline, K., Bunting, A.M., Hepler, S.A., Rivera-Aguirre, A., Krawczyk, N., Cerda, M. (2023) State-level geospatial history of overdose deaths involving stimulants in the United States, 1999-2020. American Journal of Public Health, 113(9): 991-999. (Link).
McKnight, E., Dong, Q.*, Brook, D.L., Hepler, S.A., Kline, D.M., Bonny, A. "A descriptive study of opioid misuse prevalence and office-based buprenorphine access in Ohio: a call for a targeted and flexible approach." Cureus. 15(3). (Link).
Kline, D., Waller, L.A., McKnight, E., Bonny, A., Miller, W.C., Hepler, S.A. "A dynamic spatial factor model to describe the opioid syndemic in Ohio." Epidemiology. 34(3), 487-494. (Link).
Hepler, S.A., Kline, D., McKnight, E., Bonny, A., Waller, L.A., "An integrated abundance model for estimating county-level prevalence of opioid misuse in Ohio." Journal of the Royal Statistical Society, Series A. 186(1), 43-60. (Link ).
Hepler, S.A., Kaufeld, K., Liu, X.+ Kline, D., (2022) "Integrating public health surveillance and environmental data to inform spatial risk of exposure to Histoplasma." Epidemiology, 33(5), 654-659.
Kline, D., Ji, Y.*, Hepler, S.A., (2021) "A multivariate spatio-temporal model of the opioid epidemic in Ohio: A factor model approach." Health Services and Outcomes Research Methodology, 21, 42-53. (Link).
Kline, D., Pan, Y., Hepler, S.A., (2021) "Spatio-temporal trends in opioid overdose deaths by race for counties in Ohio," Epidemiology, 32 (2), 295-302. (Link).
Hepler, S.A., Erhardt, R., (2021) "A spatiotemporal model for multivariate occupancy data," Environmetrics, 32 (2). (Link).
Hepler, S.A., Waller, L.A., Kline, D., (2021) "A multivariate spatio-temporal change point model of opioid overdose deaths in Ohio," Annals of Applied Statistics, 15(3), 1329-1342. (Link).
Kline, D., Hepler, S.A., (2021) "Estimating the burden of the opioid epidemic for adults and adolescents in Ohio counties," Biometrics, 77(2). (Link).
Kline, D., Hepler, S.A., McKnight, E., Bonny, A. (2019) “A joint spatial model of opioid associated deaths and treatment admissions in Ohio,” Annals of Epidemiology, 33, 19-23. (Link).
Hepler, S.A., McKnight, E., Bonny, A., and Kline, D. (2019) “A latent spatial factor approach for synthesizing opioid associated deaths and treatment admissions in Ohio counties,” Epidemiology, 30(3), 365-370. (Link).
Hepler, S.A., Erhardt, R., Anderson, T.M. (2018) “Identifying drivers of spatial variability with Bayesian occupancy models,” Ecology, 99(10), 2152-2158. (Link)
Hepler, S.A., Herbei, R. (2017) “A Monte Carlo approach to quantifying discrepancies between intractable probability distributions,” Journal of Statistical Computation and Simulation, 87, 8, 1666-1683. (Link)
Anderson, T.M., White, S.A., Davis, B.*, Erhardt, R., Palmer, M., Packer C. (2016) “The spatial and temporal distribution of African savannah herbivores: species associations and habitat occupancy in a landscape context,” Philosophical Transactions of the Royal Society B, 371: 20150314.(Link)
White, S.A., Herbei, R. (2015) “A Monte Carlo approach to model error quantification in Bayesian parameter estimation,” Computational Statistics and Data Analysis, 83, 168 – 181. (Link)
* Master's Degree Student, + Undergraduate student
Possible Student Projects
I frequently work with both undergraduate and graduate students on research projects related to applications in environmental, ecological, and epidemiological statistics. Click HERE for a brief presentation of some possible student research topics.
Snapshot Serengeti
You can learn more about the Snapshot Serengeti project and help out by classifying camera-trap images by clicking here.