The InventBlog has a post linking to a pdf of SMALL ENTITIES AND THE “FIRST TO INVENT” PATENT SYSTEM: AN EMPIRICAL ANALYSIS. The pdf purports to be an update of a paper in Vol. 84 of JPTOS, published in 2002, but does not seem to mention the more recent paper in Vol. 87.
The paper does acknowledge directly that "first to file" and "first inventor to file" are the same thing, contrary to a different report (discussed on IPBiz) stating that "first inventor to file" was an intermediate standard between "first to file" and "first to invent."