Questions of the Day and of the Fray number 6: Pearson, Karl. 1912. Eugenics and Public Health. A Lecture Delivered to the York Congress of the Royal Sanitary Institute, July 30th, 1912 (London: Dulau and Co.). 34 pp. This publication is reprinted from Journal of Royal Sanitary Institute. Transactions, 33 (1912), 304–335.
Summary
This lecture addressed public health officers, urging them toward scientific methodology. Pearson highlights several statistical pitfalls common in public reports:
- Standardization and Personal Equation: He insists that public health data are often compromised because assistant officers and visitors lack standardized judgment. Differences in reported prevalence (e.g., 8% versus 25% for a characteristic in the same district) often reflect the investigator’s “personal equation” rather than genuine local conditions.
- Paucity of Data: Pearson condemns the practice of drawing vast social conclusions from inadequate samples, illustrating this with Dr. Ewart’s phthisis theory based on just 79 cases. Pearson’s own analysis of Ewart’s hypothesis, using four times the data, showed that the result was not statistically significant, falling within the boundaries expected from random chance.
- Heredity vs. Environment in Alcoholism: He uses data on inebriate women to demonstrate that the apparent correlation between length of drunkenness and physical unfitness is primarily a function of increasing age. Dr. Heron’s work confirmed that when age was held constant, there was no measurable association between the duration of alcoholism and fitness.
- Infantile Mortality and Maternal Health: Analyzing mortality data in Preston and Blackburn, Pearson shows that high infantile death rates among artificially fed babies were concentrated among those where artificial feeding was necessary (i.e., the mother or baby was delicate). This indicated that the mother’s health (likely hereditary physique) was a factor 15 to 17 times stronger in determining infant survival/delicacy than environmental factors like employment or back-to-back housing.
Questions of the Day and of the Fray number 6
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