Twin Data that Made a Big Difference, and that Deserve to be Better-Known and Used in Teaching

• Main Authors: Harlan Campbell, James A. Hanley
• Format: Article
• Language: English
• Published: Taylor & Francis Group 2017-09-01
• Series: Journal of Statistics Education
• Subjects: Epidemiology; Generalized estimating equations; Global health; HIV; Matched pairs; Natural experiment; Odds ratios; Quasi-likelihood; Recall bias
• Online Access: http://dx.doi.org/10.1080/10691898.2017.1381055

Because of their efficiency and ability to keep many other factors constant, twin studies have a special appeal for investigators. Just as with any teaching dataset, a “matched-sets” dataset used to illustrate a statistical model should be compelling, still relevant, and valid. Indeed, such a “model dataset” should meet the same tests for worthiness that news organization editors impose on their journalists: are the data new? Are they true? Do they matter? This article introduces and shares a twin dataset that meets, to a large extent, these criteria. In fact, while more than two decades old, the data are still widely cited today in ongoing related research. This dataset was the basis of a clever study that confirmed an inspired hunch, changed the way pregnancies in HIV-positive mothers are managed, and led to reductions in the rates of maternal-to-child transmission of HIV.