It sounds like you're trying to say people are more likely to edit and that the retention rate is unchanged. It's hard to say what wording is appropriate without seeing the data and what it actually does support. What exactly is the data on retention?

On a related note, I'd like to point out the unanticipated results of an older project with similar goals. The Wikipedia Adventure was intended to help bring in more new editors, helping them make initial edits and giving them badges etc as motivation / positive reinforcement. While initial results seemed to indicate increase in editing, once the facilitated-edits were discounted it turned out to have a very significant NEGATIVE impact. Users who were offered The Wikipedia Adventure were less likely to go on to make edits and they made fewer edits. People tried it, they made a few worthless facilitated edits, and they quit.

What does the data show for this project if you filter out edits made by the newcomer-link-app & image-app, and the help/mentor edits made via the newcomer page? Not to mention that help/mentor edits are far more valuable and costly than newbie edits. Was there a genuine increase in new users becoming constructive editors, making useful edits themselves?