This is a long and detailed post, making two central points, one more radical and surprising than the other. The less surprising – though it certainly bears repeating – is that qualitative understanding, and particularly ethnographic understanding, is vitally important in understanding people and thus in designing systems and services. The more distinctive point is that qualitative and quantitative data are not independent of each other and more particularly that quantitative data is not neutral. Or, in the line quoted by Leisa Reichelt which led me to read the article, ‘behind every quantitative measure is a qualitative judgement imbued with a set of situated agendae’. Behind the slightly tortured language of that statement there are some important insights. One is that the interpretation of data is always something we project onto it, it is never wholly latent within it. Another – in part a corollary to the first – is that data cannot be disentangled from ethics. Taken together, that’s a reminder that the spectrum from data to knowledge is one to be traversed carefully and consciously.