| Research | Sandrah (Sandy) Eckel, Ph.D. |
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I am interested in developing and applying statistical methods that address important public health
and scientific issues. So far, my work has focused on methods and applications studying the health
effects of air pollution in vulnerable populations such as children and older adults. I predominantly
work with data from large observational cohort studies.
Statistical interests: Longitudinal models, multilevel models, effect modification, integrated models, latent variables, scaling regression coefficients, reproducible research, modern prediction techniques, evaluating predictions from models for binary outcomes Substantive interests: Environmental epidemiology, biomarkers, aging, gerontologic frailty, exhaled nitric oxide, traffic-related pollution Recent and active projects: Improved statistical modeling of extended exhaled nitric oxide data A latent variable model relating exposure to disease and a biomarker of the disease process Traffic-related pollution and exhaled nitric oxide in children Effective scaling of regression coefficients for comparision Thesis projects: Identifying effect modifiers in air pollution time-series studies using a two-stage analysis (technical report) We developed and implemented a method to systematically identify potential effect modifiers of the relationship between daily mortality counts and daily levels of ambient particulate matter in a subset of cities in the National Morbidity and Mortality Air Pollution study. Stage I models produce time-fractionated particulate matter effect estimates which are modeled as a function of candidate effect modifiers in Stage II. Surrogate models for the low physical activity criterion of frailty in older adults (technical report) Gerontologic frailty has been characterized by 5 criteria: slow walking speed, weak grip strength, unintended weight loss, exhaustion, and low physical activity. Low physical activity is one of the most time-consuming criteria to assess and it was assessed infrequently in the Cardiovascular Health Study. We developed and implemented methods that address the dual goals of: 1) streamlining the current measure of low physical activity and/or 2) filling in missing information on low physical activity, where the missingness is imposed by study design. Modification by frailty status of ambient air pollution effects on lung function in older adults in the Cardiovascular Health Study (technical report) We investigated whether gerontologic frailty modified the effects of ambient air pollution on older adult lung function in the Cardiovascular Health Study. Longitudinal assessments of lung function were related to either recent summaries of pollution and current frailty status or cumulative summaries of pollution and frailty status history. Reproducible Research: As statistical analyses become increasingly complex, we have a growing need to accurately reproduce results. I worked with Dr. Roger Peng to create an R package called 'stashR' (A Set of Tools for Administering SHared Repositories) which is part of a toolkit for conducting and distributing reproducible research, particularly in the context of the Sweave system to interweave code (in R) and text (in LaTeX). |
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teaching research lectures cv [.pdf] |
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USC Department of Preventive Medicine
2001 N. Soto Street, SSB 202B, MC-9234 Los Angeles, CA Zip: 90089 for mail, 90033 for visitors/packages Email: eckel [at] usc [dot] edu Phone: (323) 442-2030 Fax: (323) 442-2349 Office: SSB 202B |