Christopher (Chris) has more than 30 years of experience in survey methodology and public health. His expertise in sample design encompasses frame choice and construction, sample size calculations for precision requirements, stratification and clustering, and sample allocation. He has developed survey weights, calculating design weights for probability samples, nonresponse adjustment factors, and post-stratification, raking, and calibration adjustments.
Chris has worked on many analyses of the Centers for Disease Control and Prevention’s (CDC) National Immunization Survey data, including detailed tabulations of results from the NIS-Child and NIS-Teen surveys, which form the basis of CDC’s annual surveillance results for these two systems used to monitor prevalence and trends in immunization among young children and teens. He has conducted annual evaluations of Total Survey Error for the NIS-Flu survey that provides annual estimates of seasonal flu vaccination among children and teens from six months to 18 years of age. Johnson was also the lead statistician for the CDC’s Community-Based Survey of Supports for Healthy Eating and Active Living (CBS HEAL), a national survey of municipal governments and their policies and practices. For this survey he handled frame construction, sample selection, weighting, and estimation.
Before joining NORC, Chris had an accomplished career as a statistician with the federal government, working closely with epidemiologists, behavioral scientists, and medical officers at the Centers for Disease Control and Prevention. He served as supervisor of a team of statisticians and data managers and as the lead statistician for some of CDC’s flagship surveillance systems in maternal and child health (PRAMS, the Pregnancy Risk Assessment Monitoring System, a state-based survey of women with a recent birth) and HIV/AIDS (MMP, the Medical Monitoring Project, a stratified, multi-stage survey of people living with HIV). His teaching experience ranges from semester-long introductory statistics courses for undergraduates to statistical software labs for MPH graduate students to day-long short courses in the specialty of Total Survey Error.
opens in new tab"Changes to the Sample Design and Weighting Methods of a Public Health Surveillance System to Also Include Persons Not Receiving HIV Medical Care."
Journal Article | December 3, 2020
Journal Article | July 30, 2020
Journal Article | February 8, 2020
opens in new tab"Methods To Include Persons Living with HIV Not Receiving HIV Care in the Medical Monitoring Project."
Journal Article | August 1, 2019
opens in new tab"Changes in Perceived Discrimination in Healthcare Settings Reported by HIV Patients in the United States from 1996 to 2011-2013."
Journal Article | September 10, 2018
Journal Article | February 3, 2018
opens in new tab"Design and Weighting Methods for a Nationally Representative Sample of HIV-Infected Adults Receiving Medical Care in the United States – Medical Monitoring Project."
Journal Article | May 26, 2016
opens in new tab"Estimating the Number of Heterosexual Persons in the United States to Calculate National Rates of HIV Infection."
Journal Article | July 5, 2015