NSF sponsors a variety of surveys designed to collect data on the human resources devoted to science and technology in the United States, including information on worker inputs for R&D. Surveys directed at employers or institutions focus on the amount of time devoted to the performance and management of R&D. These data are reported in terms of person years, or full time equivalent (FTE) R&D jobs. Surveys directed at individuals collect data on self reported primary work activity; that is, the activity on which a scientist/engineer spends the largest proportion of time but that is not necessarily full time. This National Patterns is the first to include revised estimates of the total number of scientists and engineers (S&Es) engaged primarily in R&D activities. The national totals include an FTE count of S&Es employed by industry, the total number of Federal employees whose primary work activity is research or development, an FTE estimate of graduate students' research activity, and the number of doctorate holding S&Es working in educational or nonprofit organizations who self report their primary work activity as research, development, or the management of R&D work. These concepts are further described in appendix A.