Stephanie Ann Kovalchik is an associate statistician at the RAND Corporation. She has methodological expertise in absolute risk prediction, risk stratification, regression modeling, survey methods, meta-analysis, and hierarchical modeling. She is also an experienced R programmer and software developer, with a particular interest in designing software for statistical modeling and data visualization.
From 2011 to 2013, Kovalchik was a fellow at the National Cancer Institute, where she worked with randomized, observational, and survey study designs to develop cancer prediction models. This included a thyroid cancer prediction model for childhood cancer survivors and a model to predict the risk of lung-cancer death in smokers. She is interested in using such prediction tools to identify high-risk patient populations and evaluate the utility of health care programs that target interventions according to risk. Kovalchik earned a Ph.D. in biostatistics from the University of California, Los Angeles.
Kovalchik SA, Varadhan R, Weiss CO., "Assessing heterogeneity of treatment effect in a clinical trial with the proportional interactions model," Statistics in Medicine, 2013 (forthcoming)
Kovalchik SA, Pfeiffer R., "Population-based absolute risk estimation with survey data.," Lifetime Data Analysis, 2013 (forthcoming)
Kovalchik SA, Varadhan R, Fetterman B, Poitras NE, Wacholder S, Katki HA., "A general binomial regression model to estimate standardized risk differences from binary response data," Statistics in Medicine, 32(5):808-21, 2013
Kovalchik SA, Ronckers CM, Veiga LH, Sigurdson AJ, Inskip PD, de Vathaire F, Sklar CA, Donaldson SS, Anderson H, Bhatti P, Hammond S, Leisenring WM, Mertens AC, Smith SA, Stovall M, Tucker MA, Weathers RE, Robison LL, Pfeiffer RM., "Absolute risk prediction of second primary thyroid cancer among 5-year survivors of childhood cancer," Journal of Clinical Oncology, 31(1):119-127, 2013
Kovalchik SA, "Aggregate-data estimation of an individual patient data linear random effects meta-analysis with a patient covariate-treatment interaction term," Biostatistics, 14(2):273-83, 2013
Kovalchik SA, Tammemagi M, Berg CD, Caporaso NE, Riley TL, Korch M, Silvestri GA, Aberle DR, Gatsonis C, Chaturvedi AK, Katki HA., "Targeting of low-dose CT screening according to the risk of lung-cancer death," New England Journal of Medicine, 369(3):245-254, 2013
Kovalchik SA, Pfeiffer RM., "Re: Assessment of impact of outmigration on incidence of second primary neoplasms in childhood cancer survivors estimated from SEER data," Journal of the National Cancer Institute, 104(19):1517-8, 2012
Kovalchik SA, "Survey finds that most meta-analysts do not attempt to collect individual patient data," Journal of Clinical Epidemiology, 65(12):1296-9, 2012