Related Experiment Video
Updated: Oct 21, 2026

Inverse Probability of Treatment Weighting (Propensity Score) using the Military Health System Data Repository and National Death Index
Published on: January 8, 2020
Estimating the generalized impact fraction from case-control data
1Institute of Statistics, University of Bremen, Germany.
Abstract:
The generalized impact fraction (also called the generalized attributable fraction) was introduced by Walter (1980, American Journal of Epidemiology 112, 409-416) and Morgenstern and Bursic (1982, Journal of Community Health 7, 292-309) as a measure that generalizes the population attributable fraction (attributable risk). It is defined as the fractional reduction of a disease resulting from changing the current distribution of a risk factor to some modified distribution. We show that the point and variance estimator derived by Greenland and Drescher (1993, Biometrics 49, 865-872) for fixed shift functions can be extended to situations where the shift is a probabilistic function of the actual exposure value. The formulas are applicable for case-control designs where the cases are simply randomly selected and the controls are chosen in one of three ways: simple random sampling, stratified random sampling, and frequency matching.
Related Concept Videos
Distributions to Estimate Population Parameter
Testing a Claim about Population Proportion
There are two methods of testing a claim about a population proportion: (1) Using the sample proportion from the data where a binomial distribution is approximated to the normal distribution and (2) Using the binomial probabilities calculated from the data.
The first method uses normal distribution as an approximation to the binomial distribution. The requirements are as follows: sample size is large...
Types of Biopharmaceutical Studies: Controlled and Non-Controlled Approaches
Non-controlled studies, commonly employed for initial exploration, lack a control group, rendering them susceptible to biases and external influences. In contrast, controlled...
Strategies for Assessing and Addressing Confounding
Confounding can be addressed at both the design phase of a study and through analytical methods after data...
Actuarial Approach
Consider the example of a high-risk surgical procedure with significant early-stage mortality. A two-year clinical study is conducted,...
Kaplan-Meier Approach
