what tasks are performed inside or outside the firm has blurred, the hierarchy and structure of jobs inside firms and organizations has also blurred. In general, narrow jobs have given way to broader jobs; management positions, especially those in middle management, have been cut, leading to flatter organizational charts and much wider spans of control. Traditional boundaries around jobs, such as the distinction between managerial and production work, white-collar and blue-collar jobs, the barriers around craft work, and the narrow job descriptions of production jobs associated with scientific management have all blurred. Finally, the employment relationship defined as the set of mutual obligations and expectations between employer and employee has substantially weakened. Expectations seem to have clearly moved toward more transient relationships, although the data from the labor market have yet to show substantial changes in that direction.

Central to the theme of this volume are the implications of the changes in work structure for classification systems. For example, if careers increasingly span several employers, occupational structures based on job ladders within companies may become less important and those that cut across organizations may become more so. Career paths may increasingly be built around temporary and part-time jobs, often in combinations that do not necessarily fit with traditional notions of internal mobility. If individuals in fact will be spending more time in similar jobs, then perhaps occupational classification systems will need to broaden considerably in order to accommodate greater depth in a given occupation. For example, the classifications associated with computer programming might need to be broadened to differentiate the range of programming jobs one might have over a lifetime of doing that work and how different positions might build on each other to create an entire career.

As noted earlier, the skills, knowledge, and abilities that are demanded in the changing work structure are also different from those in the past and need to be captured by classification systems. Perhaps the biggest challenges are created by the potential for greater mobility across firms that results in the demand for more lateral hiring. Employers and employees will need better descriptions of jobs and of employee attributes in order to facili-