Among the types of data gathered were the following:
Agency budget documents;
Professional membership rosters, primarily of the American Astronomical Society and the Astrophysics Division of the American Physical Society (APS); and
Academic degree and enrollment statistics.
Specific data sources included the following:
Federal agency personnel;
Federal procurement awards databases;
AAS and APS astrophysics membership lists;
Agency and association Web sites;
NSF Division of Science Resources Studies (SRS) data resources and reports; and
The Astrophysical Journal, Astronomical Journal, Monthly Notices of the Royal Astronomical Society, Physical Review, Icarus, Nature, Science, Publications of the Astronomical Society of the Pacific, and NASA's Astrophysical Data System.
Although numerous data are available that relate to the federal funding of astronomical research, there are limitations, which in some cases are severe, on the uniformity and completeness of the data set. For instance, at both NSF and NASA, the readily available budget and procurement records often do not specifically itemize astronomical research. As a consequence, the fraction of funding going to astronomical research must sometimes be estimated as a fraction of a larger budget.
In many cases, the data on funding for a given type of astronomical research are often spread unevenly across multiple agencies and institutions. Particular examples are theory and instrumentation, subareas of astronomical research that are funded from many different sources within NASA, NSF, the Department of Energy (DOE), and private institutions.
A different type of limitation is the difficulty of finding consistent sets of data over a time span of two decades, roughly the period covered by the 1991 and the 2000 decadal surveys in astronomy.During this time, federal agencies have gone through significant changes in the way research is funded and budgets are reported. This has led to incomplete institutional coverage (i.e., data gaps) in some cases and to a difficulty in obtaining comparable data over time in other cases.
Although these limitations make it impossible to carry out a complete and detailed audit of astronomy research funding over the past 20 years, they did not prevent the committee from carrying out the objectives of this study. This was accomplished by compiling accurate year-by-year statistics on the major research expenditures in astronomy, combined with “snapshots” of selected fiscal years to provide a more detailed picture of funding patterns and their evolution over the past decade. When relevant, the committee provides clear explanations of what data are presented, their source, and the assumptions made in presenting the findings.