Pupils--the learners of both educational thought and of educational practice--exist ever more as data, as do the strictures and goals through which these pupils are pedagogically managed. I elaborate this thought by way of a single example: a particular kind of pupils whose number is reportedly on the increase, namely pupils diagnosed with attention deficit hyperactivity disorder (ADHD). In my analysis I combine Hacking's nominalist conception of human kinds and Weber's instrumental rationalism with recent thinking about the effects of digital technologies on social organising. Discussed in more detail is a key consequence from data playing a primary role in bringing together ADHD as coherent idea and practice: if ADHD is primarily the digital and instrumental product of psychiatry and education, so that ADHD is only secondarily a reliable description of behaviour, then what is to count as valid description of ADHD as behaviour will depend firstly upon the character and application of the existing database and not on actual behaviours among pupils. The article concludes with the observation that such technological products as ADHD seem notably at odds with traditional values in education. Traditional notions of education as a form of personable nurture for example seem to contrast with the instrumental disinterestedness of managing pupils as data flows. Given the latter, there seems rising need to theorise social reproduction by data and of data in contemporary education.