The proportion of faculty who teach part time on American campuses has nearly doubled in the last 30 years. In 1970, only 22 percent of faculty held part-time appointments; today, at least 42 percent teach part time-more than twice the proportion of part-time workers in the overall U.S. labor force. This shift is one of the most controversial trends in American higher education.

Proponents of hiring part-time faculty assert that most are happy with their jobs and that institutions can reduce costs and better adjust to enrollment variations. Moreover, many part-time faculty are able instructors who focus more on teaching students than on conducting research. Critics say part-time faculty are underpaid and lack the medical insurance essential in the American system of health care. They note with concern that women, who hold just over one-third of full-time appointments, hold nearly half of part-time appointments. They argue that many part-time faculty are inadequately qualified, less productive, superficially evaluated, carelessly hired, and too easily reappointed. Finally, as part-time faculty displace full-time faculty, fewer full-time faculty are available to work with students outside class. The data show that both proponents and critics are right in some respects.

Variation by Institution, Level, and Program
The use of part-time faculty varies greatly by type of institution. Whereas nearly two-thirds of community college faculty members teach part time, less than one-third of faculty in four-year institutions hold part-time appointments. The greater reliance on part-time faculty in two-year institutions partly explains the higher numbers of part-time faculty in the United States, compared to university systems elsewhere. When, however, graduate assistants are included, the proportion of full-time faculty members even in four-year institutions drops to less than half. Because part-time faculty members teach relatively more class hours per faculty member in four year institutions, the 48 percent of part-time staff at four-year schools probably teach at least 40 percent of the classes and more than half the classes in the first two years of instruction.

Although primarily associated with lower-division instruction, part-time teaching is important to upper-division and graduate instruction, especially in vocational or professional programs. The disciplines in which 40 percent or more of the appointments at four-year institutions are part time include law, communications, health sciences, teacher education, and business. In the liberal arts, only English relies on more than 40 percent part-time faculty appointments. Of course, part-time liberal arts faculty and graduate assistants teach more students in more classes; consequently, lower-division liberal arts classes account for the majority of part-time staff.

Those who teach part time are as likely as their full-time counterparts to have earned academic achievement awards as undergraduates, but their graduate preparation varies significantly. At four-year institutions, 75 percent of full-time faculty-but only 36 percent of part-time faculty-have terminal degrees. Full-time faculty selection usually follows a national search, a campus visit, and a review by prospective colleagues and administrators. Performance evaluation is recurrent, demanding, and often includes national as well as local assessment. Selection and evaluation of part-time faculty lack these procedures and is often haphazard. Moreover, though it is easier to replace an ineffective part-time instructor, the procedures do not assure that the replacement will be an improvement.

Conditions and Costs
The conditions of part-time appointment diminish productivity and effectiveness. Part-time faculty members are seldom paid for such activities as course preparation, office hours, grading, or committee work At research universities, where full-time faculty members spend more than two hours outside class on instruction-related activities for every hour in class, the part-time faculty ratio is one hour outside class to one hour inside. At community colleges, full-time faculty members spend about 48 minutes outside class on teaching-related activities for each hour they spend in class. For part-time community college faculty members, the time drops to only about 12 minutes outside class per in-class hour. Part-time faculty members publish less than full-time faculty, except in community colleges, where there is little research in general due to the heavy teaching loads of full-time faculty. Variations in research activity may be consistent with institutional mission, but declines in the proportion of time devoted to out-of-classroom instructional activities are not.

Part-time appointments are less expensive. With payment typically ranging from $1,000 to $3,000 per course, institutions can reduce per-unit instructional cost by one-half to two-thirds. But buying cheap is not always economical. Reliance on part-time faculty is greatest in lower-division liberal arts programs, where students are most in need of faculty support and are least likely to find it.

Employment conditions for part-time faculty vary greatly by field of instruction. Part-time liberal arts faculty more often than part-time vocational faculty, lack other part- or full-time employment and, therefore, tend to be less satisfied. Their average income is two-thirds that of vocational instructors in community colleges and 55 percent of average salaries at four-year institutions. Liberal arts part-time faculty in general-nearly two-thirds of these women-report they would prefer but cannot find full-time academic appointments. These differences help explain why proponents and critics of hiring part-time faculty often talk past one another. Satisfied part-time instructors, whose outside jobs often contribute to their instructional effectiveness, more often teach in vocational programs. Dissatisfied faculty, who lack time and opportunity to maintain their professional skills, more often teach in lower-division liberal arts programs.

Policymakers commonly attribute shortcomings in faculty-student involvement to declines in full-time faculty teaching loads rather than to increased reliance on part-timers. This thinking ignores two facts. First, instructional hours vary with institutional mission. Faculty members spend more hours in class at two-year and bachelor's-degree-granting institutions than at comprehensive or research universities. Second, as teaching loads increase, out-of-class instructional time diminishes. Improving the quality of instruction requires that institutions that have relied excessively on inadequately supported part-time appointments increase their proportion of full-time appointments and improve the support for and quality of their part-time appointees.