John Graunt: A Tercentenary Tribute

John Graunt was a London draper who, three hundred years ago, published some "Natural and Political Observations on the Bills of Mortality". These observations represent the first, and an extremely competent, attempt to draw scientific conclusions from statistical data. The present study illustrates Graunt's careful scientific approach, his ability to extract the essence from what by modern standards are distinctly untrustworthy demographic data, and his intuitive appreciation of the amount of interpretation his findings would stand. Graunt's analysis was largely based upon ratios and proportions of vital events and consideration of the way in which these altered in different circumstances, and is remarkably free of major statistical errors. His statistical understanding was considerable; for example, we owe to him the first scientific estimates of population size, the concept of the life table, the idea of statistical association, the first studies of time series, and a pioneer attempt to draw a representative sample. Graunt's book is well worth reading today, not only for entertainment and instruction, but because it laid the foundations of the science of statistics.