In this age of metrics everywhere and big data, the data on inequality, a very important social issue, took Piketty and his collaborators, all professional economists, many years of research to assemble and publish.
This data is not even big: to paraphrase a joke I read on HN recently, you could do the analysis in Excel and it wouldn't even crash.
There is something to be said for systematically gathering a lot more data than governments collect now, especially income and wealth data in this case. Not because it benefits anyone economically right now, but because without collecting it now, it is that much harder to reconstruct it later.
The primary issue here is how you can define "wealth" or "rich" and "poor." Income's one measure, sure. But what about the trust fund kids? What about college kids?
The real problem with collecting data like this is that there's no real good source of it. Most of what you get has selection bias, and the other stuff you can get is riddled with holes. And then you try to do it across countries, where definitions change and governments college disparate data at differing granularities and it just gets...frustrating.
An economist's toughest job is finding good data. The analysis is the easy part!
This data is not even big: to paraphrase a joke I read on HN recently, you could do the analysis in Excel and it wouldn't even crash.
There is something to be said for systematically gathering a lot more data than governments collect now, especially income and wealth data in this case. Not because it benefits anyone economically right now, but because without collecting it now, it is that much harder to reconstruct it later.