all other occupations. When there are two or more occupations in a group (as defined by the first three digits of the code), then they are assigned codes alphabetically, in multiples of four. Occupations are grouped by "similarity" according to the information contained in the body of the definition, i.e., the lead statement and the task element statements.
The data in the DOT are collected by occupational analysts in U.S. Employment Services offices using methods described in the Handbook for Analyzing Jobs (U.S. Department of Labor, 1991). Essentially, the occupational analyst observes and interviews workers on the job and then completes a job analysis report. The handbook contains instructions for completing this report, including lists of codes and anchors for rating scales to rate data, people, and things. These dimensions are the crux of functional job analysis, a methodology developed by Sidney A. Fine during the 1950s (Fine and Wiley, 1971); it begins with the premise that all worker-job situations are an interplay of the worker with the dimensions of data, people, and things. The purpose of job analysis is to ascertain the functionality of the relationship of the worker to data, people, and things—that is, the complexity of interplay with elements needed to accomplish task objectives. In addition, the fourth edition of the DOT has associated data on just over 60 variables. These include training time, aptitudes, interests, temperaments, and various physical demands and working conditions. Most of the variables are binary in form. The last time the variables were systematically updated was in the middle 1970s, and some would argue (National Research Council, 1980) that this update was minimal, hence the data refer to the world of work in the middle 1960s. This is a serious limitation in a world of work that is changing.
Evaluations of the DOT lauded its value and high level of use by government agencies, researchers, and others concerned with occupational information, but they tended to criticize its unwieldy size and the growing disparity between its definitions and the real world of work (National Research Council, 1980; Spenner et al., 1980; Advisory Panel for the Dictionary of Occupational Titles, 1993). The DOT's principal weaknesses were identified: