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A 1972--1981 health survey in The Hague, Netherlands, discovered an association between keeping pet birds and increased risk of lung cancer. To investigate birdkeeping as a risk factor, researchers conducted a case--control study of patients in 1985 at four hospitals in The Hague (population 450,000). They identified 49 cases of lung cancer among the patients who were registered with a general practice, who were age 65 or younger and who had resided in the city since 1965. They also selected 98 controls from a population of residents having the same general age structure.




A data frame with 147 observations on the following 7 variables.

  • LC Whether subject has lung cancer

  • FM Sex of subject

  • SS Socioeconomic status, determined by occupation of the household's principal wage earner

  • BK Indicator for birdkeeping (caged birds in the home for more that 6 consecutive months from 5 to 14 years before diagnosis (cases) or examination (control))

  • AG Age of subject (in years)

  • YR Years of smoking prior to diagnosis or examination

  • CD Average rate of smoking (in cigarettes per day)


Ramsey, F.L. and Schafer, D.W. (2013). The Statistical Sleuth: A Course in Methods of Data Analysis (3rd ed), Cengage Learning.


This dataset is copied and renamed from the Sleuth3 R package, where it is called case2002.


Holst, P.A., Kromhout, D. and Brand, R. (1988). "For Debate: Pet Birds as an Independent Risk Factor for Lung Cancer" British Medical Journal 297: 13--21.