Kobo evidently are doing some analysis on completion rates, and published a report last year aimed at publishers using analysis based on similar metrics:

http://cafe.kobo.com/_ir/159/20149/Publishing%20in%20the%20E...

Further numbers into completion rates split by region and genre also from Kobo made their way into this nytimes article earlier in the year: http://www.nytimes.com/2015/02/05/arts/international/keeping...

I'd be interested in the raw data, particularly also from Amazon based on Kindle ebook read completion though I imagine that won't get shared.

Nice find. Yes raw data will be more useful. Especially, with Amazon's Pay-Per-Page for Kindle Unlimited, if such data is available, it will be interesting to see how authors reverse engineer this process to achieve maximum page views (and completion rates)

This really would be interesting. I'd like to see data on overall completion % for ebooks. Assessing those books which tend to be completed once started would help identify the more interesting books.

Combined with top selling book lists, this would provide a good filter to decide on potential new reads and could form the heart of improved book recommendation services.