Doctoral programs across the nation took a collective pause Tuesday to peruse a long-awaited report that offers the first definitive rankings of the programs in 15 years. It might take a doctorate to fully comprehend the National Research Council rankings. Instead of ranking programs from first to last, the report states each ranking as a statistical range. So, we now know that the comparative literature program at the University of Maryland ranks somewhere between sixth and 19th among 46 like programs nationwide. And that's just one ranking. The report rates programs two different ways, adding to the confusion. Universities seized on their more flattering rankings as affirmations of their better programs. Doctoral departments rely on the highly regarded NRC rankings to attract students and faculty. 'I've said to undergraduates who want to go to graduate school in history that if you can't get into a top-10 program, don't go. That's how significant this is,' said Edward Ayers, a history scholar who is president of the University of Richmond. The rankings cover 5,000 doctoral programs in 62 fields at 212 institutions and is billed as the largest comparative analysis of its sort to date. The rankings are based on 2006 data, which makes them rather dated. Then again, the programs hadn't been ranked since 1995. Predictably, the top Ivy League schools and the premiere University of California campuses earn the highest rankings in many fields. Johns Hopkins University in Baltimore earns premiere rankings in history, astrophysics, linguistics, neurobiology and nursing, among other fields, meaning that Hopkins is listed among a handful of schools whose ranking could be as high as one, two or three. The University of Virginia ranks high in Spanish and Portuguese and pharmacology. Virginia Tech excels in forestry. Top-rated and ascendant programs will waste no time spreading the word, while low-rated offerings will fall under closer scrutiny, education leaders said. 'It is an affirmation if you're doing well, and it is reason to question if you're at the bottom,' said Arthur Garson, provost of U-Va. 'You don't ever want to sit on your laurels with a top program. . . . The bottom ones, you really do need to make an affirmative decision of three things to do: grow it, keep it the same or shrink it. You can't leave it alone.' Department heads may have a hard time synthesizing the rankings into a press release. They're more complicated than past rankings from the research council. Each program is ranked once according to characteristics such as faculty publications and how long it takes students to earn a degree. (The longest doctoral program in the nation is the music program at Washington University in St. Louis, with a median length of 16.3 years, according to the Chronicle of Higher Education.) A second ranking derives from each program's reputation, as measured by the academic community. Jeremiah Ostriker, chairman of the project, told the Chronicle the raters rejected simple best-to-worst rankings because they offered 'spurious precision.' He said of the resulting jumble of numbers, 'It's a little unsatisfactory, but at least it's honest.' 