摘要：Harlan Campbell a * & James A. Hanley b a Department of Statistics , University of British Columbia, Vancouver , BC , Canada b Department of Epidemiology, Biostatistics and Occupational Health , McGill University , Montreal , QC , Canada CONTACT Harlan Campbell harlan.campbell@stat.ubc.ca Department of Statistics , University of British Columbia , 3182 Earth Sciences Building, 2207 Main Mall, Vancouver , BC V6T 1Z4 , Canada 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.
