The results of a major survey:

http://www.writersworkshop.co.uk/blog/do-you-love-your-publisher-the-results-of-our-survey/

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And the question-by-question data, with comments:

http://www.writersworkshop.co.uk/blog/do-you-love-your-publisher-the-results-of-our-survey/

Bit of loaded question - Do you Love Your Publisher and I'm not sure a private company promoting editorial services is the best arbiter of data about editing standards,the conclusionsare all a bit aren't editors just wonderful for me. Interesting data none the less: http://www.writersworkshop.co.uk/blog/author-survey-the-data/

As a constant reader I see dreadful and good editing everywhere and I've had both good and bad editing on my own books. A less loaded survey question would have been Rate Your Publishers Performance.

What was more interesting was the data collected on author income 58.9% earn less than 5k per year.

Another reason to go back to a proper writing job.