Who benefits in first to file?
The paper, titled "Competition, Innovation and Racing for Priority at the U.S. Patent and Trademark Office," (Brookings Working Paper 05-22. Nov 2005) does not cite the paper by Gerald Mossinghoff, entitled THE FIRST-TO-INVENT RULE IN THE U.S. PATENT SYSTEM HAS PROVIDED NO ADVANTAGE TO SMALL ENTITIES, 87 J. Pat. & Trademark Off. Soc'y 514.
The data provided by the USPTO confirm empirically that the current first-to-invent system of priority provides no advantage to small entities. Figure 6 speaks for itself. Historically, virtually the same number of small entities were advantaged by the first-to-invent system (286) as were disadvantaged (289). And with respect to independent inventors -- among the most vocal of first-to-invent adherents -- more were disadvantaged (167) than were advantaged (139) by the first-to-invent system.
Given that the Mossinghoff paper appeared in the same month that H.R. 2795 was circulated, one understands that small inventors were on notice of their "disadvantage" in the first to invent system, but generally opposed the first to file aspect of H.R. 2795 anyway. Suitable inquiry into that aspect might be made by those discussing the first to invent disadvantage.
In this, a separate inquiry is whether small entities and independent inventors improve their situation in "first to file." If they don't, then their behavior might be quite rational.
Separately, I had written of difficulties that universities would have with "first to file" in "Patent reform 2005: sound and fury signifying what?" in the New Jersey Law Journal, July 18, 2005, otherwise discussing issues with H.R. 2795. [You won't find the article text in a Google search, but it is on LEXIS.]