The number of US faculty members who have tenure or are on the tenure track is falling, according to a report by the American Association of University Professors in Washington DC. Over the past 40 years, the proportion of the academic labour force that is in a full-time tenured position has shrunk by one-quarter, and the proportion in tenure-track posts has halved, reports Higher Education at a Crossroads. In 2014, the study found, 21% of faculty appointments were full-time tenured and 41% were part-time. On average, male professors earned more than female professors in full-time positions at every rank and across all types of institution. Overall, positions in New England paid the most, whereas those in Iowa, Kansas, Minnesota, Missouri, Nebraska, North Dakota and South Dakota paid the least. The report also found that part-time appointees were less likely to conduct long-term research and experiment with teaching methods and course content. Citing a correlation between lower student-graduation rates and increases in the number of part-time and non-tenure-track positions, the association calls for institutions to convert part-time, non-tenure positions into tenure-track posts.