Last week, the National Institutes of Health (NIH) announced that the success rate for research grants, a closely watched indicator of how well investigators are doing in the struggle for funds, fell to an all-time low in 2011: 18%. At first glance, the drop appears to be due to increased competition, reflected in a steep rise on applications last year. But several other factors are also at play, including budget decisions made years ago, says NIH extramural research chief Sally Rockey.
The success rate is the number of funded grants divided by reviewed applications. The 18% success rate, announced  by Rockey on her blog, is down 3% from 2010 and is slightly higher than a preliminary estimate  last fall. It continues a decline from success rates of around 30% a decade ago when NIH's budget was growing. Part of the explanation is that the denominator is larger: investigators sent a record 49,592 research grant proposals to NIH last year, an 8% rise.
But that's not the whole story, Rockey says in a blog post  today. Much of the rise is explained by a 17% increase in proposals for a specific category of funding—short-term R21 grants. The mainstay for most labs is the larger R01, NIH's individual investigator-initiated grant, for which the success rate slid from 22% in 2010 to 18% in 2011. Applications rose 3% for R01s. Another reason for success rate slippage is that NIH funded fewer R01 grants copmpeting compared with 2010. That's partly because the size of the average grant grew slightly and because NIH had less to spend overall on R01s (its budget was cut 1% last year).
But the most important factor, accounting for 1.5% of the success rate drop, is that a larger portion of R01 money than usual was tied up in already-awarded grants. Because most NIH grants last 3 to 5 years, each award creates several years of unfunded future commitments. The amount of money needed for these ongoing grants rose by $189 million in 2011, Rockey reports. "This demonstrates how carefully we need to manage our funds since funding decisions in any one year have implications for the out years," she writes. She posted a graph  showing how the share of NIH's R01 money committed to ongoing grants fluctuates year to year. In 2011 it jumped to 78%, the highest level in 4 years.
A close NIH observer, Howard Garrison of the Federation of American Societies for Experimental Biology, says managing that out-year commitment is a delicate balancing act for the agency. If NIH gets a generous increase one year and doesn't fund more grants, "People like me go crazy because the money isn't going out on the streets," he says. Yet if Congress cuts NIH's budget a couple of years later and NIH's commitment has grown, "you're toast," and success rates plunge.
Rockey's bottom line: "The success rate is complicated and it's not just a single factor" that drives it, she told ScienceInsider. She adds that success rates don't necessarily reflect "the quantity of science" NIH is funding. The pool of funded investigators has remained fairly steady in recent years, she says.
Although NIH received a modest 0.8% increase in 2012, the agency appears to be girding for a period of austerity. A notice  today states that continuing grants will get no inflationary increase in 2012 and new awards will not receive inflationary increases in future years.