American universities continued to increase the number of doctoral degrees they award -- but just barely -- in 2008. And if it weren't for biology, there would have been virtually no increase at all.

The National Science Foundation on Thursday published an initial report of data from the Survey of Earned Doctorates, an annual study sponsored by the science foundation and five other federal agencies and conducted by the University of Chicago's National Opinion Research Center.

The survey -- which has been tinged by controversy since last year over decisions to withhold some data on the race and ethnicity of degree recipients, citing privacy concerns -- is closely watched as an indicator of the health and vitality of the American research enterprise and of graduate education in the United States.

To the extent that that health and vitality are appropriately measured by the number of freshly minted doctorates produced -- an approach that not everyone would embrace, given concerns about the job market in some fields and plans to shrink Ph.D. programs at some universities -- the new data from the NSF may prompt some concerns. While the number of doctorates awarded grew for the sixth straight year, to 48,802 from 48,112 in 2007, the proportional (1.43 percent) and numerical increases were the smallest since 2003.

As seen in the table below, the results varied enormously by field and discipline. Virtually all of the growth occurred in the sciences, though, and most of that in a relative handful of fields -- the number of doctorates awarded in the biological sciences grew by about 600 (or 8.6 percent), for instance.

The social sciences saw growth of 3.5 percent between 2007 and 2008, while the number of humanities Ph.D.'s awarded continued a several-year nosedive, dipping 7.1 percent in 2008 on top of a 5.3 percent drop from 2006 to 2007. Oddly, all of the major humanities fields listed in the NSF report (literature, history, languages and religion) showed increases in 2008, but the catchall category of "other humanities" (philosophy, archaeology, etc.) showed a steep decline of nearly 33 percent.

Number of Doctorates Awarded by U.S. Universities

Source: Survey of Earned Doctorates

The demographics of doctorate earners remains of intense interest not just to graduate deans and provosts concerned about the ethnic diversity of the future professoriate, but to policy makers interested in ensuring that the products of American research universities stay in the U.S. to bolster the economy.

On those fronts, too, the 2008 data are mixed. Women accounted for more of the increase in science and engineering doctorates than did men (by a 699 to 337 margin), and the number of temporary visa holders who received doctorates grew only slightly, by 0.7 percent. The number of doctoral recipients in science engineering fields increased for all races except for American Indians/Native Alaskans.

And far greater proportions of doctorate recipients who hold temporary visas said their "postgraduation commitments" would keep them either working or training in the United States in 2008 than was true five years earlier, the NSF report found.