The Spring 2014 issue of The NLN Report includes an article on the long-term impact on ongoing writing behaviors of the NLN Scholarly Writing Retreat. See here http://www.nln.org/publications/pdf/2014SpringNewsletterfinal_.pdf and scroll to page 10.
Of 111 participants, 62 responded to an outcomes survey; of those 61 submitted manuscripts. Eighty percent were published, with an additional 11.5 percent still in review.
More about the fall writing retreat here: http://www.nlnfoundation.org/Scholarly_Writing_Retreat_Fall_2014.cfm