A smashing example of how data can both clarify and obfuscate. On balance this is a fantastic piece that brings much-needed information to the discussion and what is more provides a free download of that very data. That’s almost unheard of! On the downside, I have some misgivings about the section dealing with income estimates based on unit numbers which are themselves estimates. This is further compounded by the fact that the royalty split is never as easy to assume as the current model assumes, for instance non-US authors may not earn 70% on all sales that would appear to be 70% sales for a variety of reasons. Even allowing for these complications the data gathered is very impressive indeed.
One of the most fascinating sections though is this conclusion here:
Our first thought was that top self-published authors can put out more than one work a year, while Big Five authors are limited by non-compete clauses and a legacy publishing cycle to a single novel over that same span of time. Indie authors are most likely earning more simply because they have more books for sale. Was this skewing our results? We ran another report to find out, and to our surprise, it turns out that only the handful of extreme earners have this advantage. Most self-published authors are, on average, earning more money on fewer books:
This suggests that the earnings discrepancy will grow greater over time, as self-published authors develop deeper catalogs.
Eoin Purcell's Blog 
If it was all about money, maybe we’d all self-publish. I like the imprimatur of a decent publisher. New Island’s name on my book, and their wide expertise behind me, is worth more than the potential dosh in self-publishing. Mind you, even if I did self-publish who is to say anyone would buy? I’m not sure lit fic is what buyers want. Now if I could write a paranormal romance or some such….
Nuala, that’s the truth, if it were all about money the world would be a lot worse off! It’s funny that you say that about genre choice, in the data they expressly focus on what genres are selling, the mysteries, romances and sci-fis. In some ways I think that Hugh is coming from a very different, but no less valid, philosophy to many writers and that’s where his perspective seems to come from!