Influence of Authorship on Google Rankings
Search engine optimization professionals who are "in-the-know" realize that authorship isn't used for rankings at Google.
There are obviously benefits to implementing authorship (improved click-through rate) because of the added image in the search results) but what a recent Google Webmaster Help thread indicates is that authorship only plays a role with the "in-depth-articles" feature. Outside of that, authorship has no effect on search at all.
So, should you implement authorship markup on your website? Google's John Mueller provided another way to look at the issue:
"I think it's a great thing to set up, but I wouldn't assume that it has any effect on normal rankings at all. We use over 200 factors in our crawling, indexing, and ranking, and we regularly make changes to our algorithms, so there are many potential reasons why a site might go up or down in rankings. My recommendation is not to focus too much on your competitors, but rather to work on making your site the by far absolute best of its kind -- focus on your users, don't focus on your competitors' sites."