Richard J. Murnane

Implications for Teacher Supply and Methodological Lessons for Research

Attempts to determine whether enough qualified teachers will be available to staff the nations schools in the coming years have been hampered by methodological difficulties that are inherent in the study of teacher career patterns. In this article, we have applied an analytic technique rarely used in educational research, proportional hazards modeling, to resolve these problems and to investigate the relationship between teachers background characteristics and their career durations. We find that teacher demographic characteristics and subject specialty are important predictors of length of stay in teaching. Our results call into question several assumptions about teacher career persistence implicit in the national teacher supply and demand model. We also argue that proportional hazards modeling has wide applicability to many educational research questions.

Skill Demand, Inequality, and Computerization: Connecting the Dots

Inequality has social costs: it may engender political divisions, aggravate crime, and lead low-income families into poverty from which they or their children may not emerge. Dramatic shifts in relative well-being therefore demand attention. In the late 1980s, economists discovered that the earnings of high- and low-wage workers were rapidly diverging (Levy and Murnane 1992). Chart 1 plots earnings inequality for the years 1963 to 1995, measured as the percentage difference in earnings between the 90th percentile worker and the 10th percentile worker.1 Between 1963 and 1979, this difference in earnings hovered steadily at approximately 220 percent among men and 190 percent among women. Over the next ten years, these gaps grew into fissures. The 90–10 weekly earnings differential expanded by 110 percentage points for both genders between 1979 and 1989 and then edged slowly upward throughout the 1990s. Mirroring these trends, educational earnings inequality—the earnings gap between college and high school educated workers—increased by two-thirds in the same decades (Chart 2). By 1999, educational inequality easily exceeded its high set in 1940, the earliest year for which consistent data are available.