http://www.washingtonpost.com/blogs/ezra-klein/post/did-the-stimulus-work-a-review-of-the-nine-best-studies-on-the-subject/2011/08/16/gIQAThbibJ_blog.html#pagebreak

7/9 studies said yes.

And the infamous still unpublished Conley/Dupor study is there as well.