31 We looked briefly at difference in occupational skills and working conditions between truck driving and non-driving occupations, based on data from the Dictionary of Occupational Titles ( DOT ). In comparison to the sample-weighted occupations of our control group, truck driving tended to rate somewhat lower in terms of skill and training requirements, while rating similarly in terms of working conditions. We did not pursue this approach because the DOT data file makes no distinction among drivers for trucking firms or in private carriage, or between union and nonunion drivers, thus providing no insight into the source of driver differentials by sector or union status. DOT values were adopted from England and Kilbourne (1988), who provide means of DOT variables for approximately 500 1980 Census occupational categories, calculated as weighted averages across roughly 12,000 DOT occupations (special Census projects mapped CPS workers to DOT occupations and 1980 Census of Population respondents to both 1970 and 1980 Census occupational codes). For a description and analysis of the DOT , see Miller, et al. (1980).
32 how labor markets work, and allows us to observe the creation and dissolution of economic rents. The approach used in this study can be characterized as quasi-experimental. In order to evaluate the "treatment" effect of deregulation on the labor market, we: 1) examine differences in labor market outcomes before and after deregulation in the treated (i.e., for-hire) sector of the motor carrier industry, 2) measure the difference- in-differences between the regulated (for- hire) and unregulated (private carriage) markets in which drivers are employed, and 3) measure the difference-in- differences in labor market outcomes for "treated" drivers, non-treated drivers, and an economy-wide group of male non-driver non-professional workers, with controls for measurable characteristics. The evidence presented here and in previous work provides what we believe is a relatively clear story. The evolution of the powerful Teamsters union during the period of ICC regulation facilitated the capture of sizable wage gains for its members. Regression analysis of truck driver and non-driver wages for 1973-1995 suggests that relative wages for drivers in the previously regulated for-hire sector fell about 15 percent as a result of deregulation. Mean driver wages in the trucking industry fell primarily because of real wage declines among union drivers, and the shift of traffic and employment from high wage union to low wage nonunion companies. While we find significant wage decreases following deregulation among union for-hire drivers, smaller wage declines are found for nonunion for-hire drivers and for union and nonunion private carriage drivers. Indeed, changes in the real wages of nonunion for-hire drivers and union and nonunion private drivers largely mirrored economy-wide wage changes among a non-driver male control group. Within the for-hire sector, union premiums fell immediately following deregulation, while union premiums within the private carriage sector were little affected by deregulation.
You've reached the end of your free preview.
Want to read all 49 pages?