Abstract
The article is organised around three themes, each one illuminating half a century of historical life: (i) the first theme relates to the second half of the nineteenth century, analysing the role of statistics in the formation of state education systems; (ii) the second theme concentrates on the first half of the twentieth century and the importance of tests, examinations and surveys in the development of ‘pedagogical modernity’; (iii) the third theme looks at the historical period of the second half of the twentieth century, and how databases began to be used as an important tool in the formulation of educational policies. To conclude, the article underlines how comparison is becoming one of the main instruments of governance in contemporary societies — in other words, how power tends increasingly to be exercised through policies that claim to be ‘obvious’, ‘natural’, ‘evidence-based’, instead of being grounded on ideological and political options.