Requirements for such information may be met in a variety of ways, for example, through the use of statistics generated in the many data collection efforts undertaken by governmental and nongovernmental organizations. While necessary, however, statistical information is not always sufficient. Many decisions involving human resources must be based on qualitative factors (e.g., personality, work experience, functional competencies) that are difficult to summarize in a data set. Moreover, no single set of information is able to satisfy the needs of all potential users. Recruiters for an individual company may need more detailed information than do those who formulate national policy on R&D or student support. Given the variety of data collection efforts and user needs, it is not surprising to find that the computing professions are one group for which, depending on one's perspective, there are no data, poor data, and/or conflicting data. Even in a very narrow category such as Ph.D.s in computer science, counts of the number of people differ.
Current data on computing professionals reflect two classes of problems: (1) common difficulties encountered in gathering data and (2) uncommon disagreement about how to label and categorize computing professionals. Difficulties of the first type are largely methodological and include inconsistencies arising from differences in responding units (e.g., university registrars, personnel managers, individuals) as well as in how individuals might report when faced with alternative lists of fields, occupations, responsibilities, or skills.1 Third-party counts typically do not agree with self-reporting counts, and discrepancies are compounded by the fact that data-gathering activities differ in focus and purpose, geographic scope, how nonrespondents are handled, sampling, and aggregation of data.
Data-gathering errors, although inevitable, are a special concern in analyzing occupations employing small numbers of people. In total, computing professional occupations, plus related technical occupations, appear to employ about 1 million workers, or less than 1 percent of the total U.S. work force—but also 7 percent of what the Bureau of Labor Statistics calls ''professional specialty'' occupations, a remarkable level for an occupational group that is less than 30 years old. Moreover, these occupations are changing dramatically, and this dynamism creates problems for classification and reporting. Commented Barbara Wamsley, deputy director, Federal Programs, National Academy of Public Administration, "By the time you get the standard written for the job, the job has changed."