albeit much more superficially than do situated studies. For some lines of work, especially management, there is almost no research on which to draw. In these instances, students of the changing nature of work must, at present, turn to accounts written by consultants and managers and then attempt the difficult interpretive task of separating self-serving rhetoric from substantiated observations.
Ideally, researchers and policy makers should be able to turn to a continually updated, national, and longitudinal database on job skills and occupational structures to identify with less ambiguity the kinds of trends with which this committee has wrestled. Unfortunately, it is precisely the absence of such a database that occasioned this report in the first place. We do not believe, however, that the absence of systematic and consistent data on a large number of occupations precludes drawing any conclusions whatsoever. Although the data are uneven, accumulating evidence concerning some occupational groups does seem to point in consistent directions. It is reasonable to treat these consistencies as a form of replication that constitutes reasonable evidence. And it is equally important to underscore where there is considerable variation in what researchers have observed as well as to indicate what we do not, but should, know.
At the moment, evidence for what is happening to blue-collar jobs, especially jobs in manufacturing settings, is the most well developed and consistent. Our relatively greater understanding of the changing content of blue-collar work probably reflects several facts. First, social sciences have a long history of studying factory work, so there are baselines for judging change. Second, it is much easier for researchers to gain access to blue-collar settings than it is to gain access to any other type of work, with the possible exception of clerical, technical, and professional work. Third, techniques for describing and analyzing physical work are better developed than techniques for describing and studying mental and interpersonal work. Finally, the transformation of production processes has been a key concern in business and engineering since the early 1980s and hence has attracted considerable attention from responsible journalists.
Aside from the well known fact that blue-collar employment has fallen precipitously since mid-century, four other develop-