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Work, Jobs, and Occupations: A Critical Review of the Dictionary of Occupational Titles (1980)

Chapter: 8 The Classification of Occupations: A Review of Selected Systems

« Previous: 7 An Assessment of the Dictionary of Occupational Titles as a Source of Occupational Information
Suggested Citation:"8 The Classification of Occupations: A Review of Selected Systems." National Research Council. 1980. Work, Jobs, and Occupations: A Critical Review of the Dictionary of Occupational Titles. Washington, DC: The National Academies Press. doi: 10.17226/92.
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Suggested Citation:"8 The Classification of Occupations: A Review of Selected Systems." National Research Council. 1980. Work, Jobs, and Occupations: A Critical Review of the Dictionary of Occupational Titles. Washington, DC: The National Academies Press. doi: 10.17226/92.
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Suggested Citation:"8 The Classification of Occupations: A Review of Selected Systems." National Research Council. 1980. Work, Jobs, and Occupations: A Critical Review of the Dictionary of Occupational Titles. Washington, DC: The National Academies Press. doi: 10.17226/92.
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Page 198
Suggested Citation:"8 The Classification of Occupations: A Review of Selected Systems." National Research Council. 1980. Work, Jobs, and Occupations: A Critical Review of the Dictionary of Occupational Titles. Washington, DC: The National Academies Press. doi: 10.17226/92.
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Page 199
Suggested Citation:"8 The Classification of Occupations: A Review of Selected Systems." National Research Council. 1980. Work, Jobs, and Occupations: A Critical Review of the Dictionary of Occupational Titles. Washington, DC: The National Academies Press. doi: 10.17226/92.
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Page 200
Suggested Citation:"8 The Classification of Occupations: A Review of Selected Systems." National Research Council. 1980. Work, Jobs, and Occupations: A Critical Review of the Dictionary of Occupational Titles. Washington, DC: The National Academies Press. doi: 10.17226/92.
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Page 201
Suggested Citation:"8 The Classification of Occupations: A Review of Selected Systems." National Research Council. 1980. Work, Jobs, and Occupations: A Critical Review of the Dictionary of Occupational Titles. Washington, DC: The National Academies Press. doi: 10.17226/92.
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Page 202
Suggested Citation:"8 The Classification of Occupations: A Review of Selected Systems." National Research Council. 1980. Work, Jobs, and Occupations: A Critical Review of the Dictionary of Occupational Titles. Washington, DC: The National Academies Press. doi: 10.17226/92.
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Page 203
Suggested Citation:"8 The Classification of Occupations: A Review of Selected Systems." National Research Council. 1980. Work, Jobs, and Occupations: A Critical Review of the Dictionary of Occupational Titles. Washington, DC: The National Academies Press. doi: 10.17226/92.
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Page 204
Suggested Citation:"8 The Classification of Occupations: A Review of Selected Systems." National Research Council. 1980. Work, Jobs, and Occupations: A Critical Review of the Dictionary of Occupational Titles. Washington, DC: The National Academies Press. doi: 10.17226/92.
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Page 205
Suggested Citation:"8 The Classification of Occupations: A Review of Selected Systems." National Research Council. 1980. Work, Jobs, and Occupations: A Critical Review of the Dictionary of Occupational Titles. Washington, DC: The National Academies Press. doi: 10.17226/92.
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Page 206
Suggested Citation:"8 The Classification of Occupations: A Review of Selected Systems." National Research Council. 1980. Work, Jobs, and Occupations: A Critical Review of the Dictionary of Occupational Titles. Washington, DC: The National Academies Press. doi: 10.17226/92.
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Page 207
Suggested Citation:"8 The Classification of Occupations: A Review of Selected Systems." National Research Council. 1980. Work, Jobs, and Occupations: A Critical Review of the Dictionary of Occupational Titles. Washington, DC: The National Academies Press. doi: 10.17226/92.
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Page 208
Suggested Citation:"8 The Classification of Occupations: A Review of Selected Systems." National Research Council. 1980. Work, Jobs, and Occupations: A Critical Review of the Dictionary of Occupational Titles. Washington, DC: The National Academies Press. doi: 10.17226/92.
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Page 209
Suggested Citation:"8 The Classification of Occupations: A Review of Selected Systems." National Research Council. 1980. Work, Jobs, and Occupations: A Critical Review of the Dictionary of Occupational Titles. Washington, DC: The National Academies Press. doi: 10.17226/92.
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Suggested Citation:"8 The Classification of Occupations: A Review of Selected Systems." National Research Council. 1980. Work, Jobs, and Occupations: A Critical Review of the Dictionary of Occupational Titles. Washington, DC: The National Academies Press. doi: 10.17226/92.
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Suggested Citation:"8 The Classification of Occupations: A Review of Selected Systems." National Research Council. 1980. Work, Jobs, and Occupations: A Critical Review of the Dictionary of Occupational Titles. Washington, DC: The National Academies Press. doi: 10.17226/92.
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Suggested Citation:"8 The Classification of Occupations: A Review of Selected Systems." National Research Council. 1980. Work, Jobs, and Occupations: A Critical Review of the Dictionary of Occupational Titles. Washington, DC: The National Academies Press. doi: 10.17226/92.
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o The Classification of o Occupations: A Review of Selected Systems THE CLASSIFICATION STRUCTURE OF THE DOT The purpose of the DOT occupational classification system is to organize occupations into groups that are similar in the sense that they tend to make similar demands on workers or in which workers with specific qualifications or characteristics are likely to find satisfactory employment. The first edition DOT noted in its foreword (p. xi): As a product of the [Employment Service] Research Program, [the DOT] is part of a directed effort designed to furnish public employment offices in this country with information and techniques that will facilitate proper classification and placement of work seekers. Getting qualified workers into appropriate jobs is a task that can be done most adequately when the transaction is based on a thorough knowledge of both worker and job.... Thus, it becomes part of the duties of public employment offices to learn as much as possible about jobs and workers in order to be able to act as an effective placement agency. If a foundry superintendent wants the public employment office to send him a cupola tender, the office must know enough about the work and worker to be able to refer a registrant who has been previously classified as qualified and capable of doing the work required. The DOT was developed to provide Employment Service interviewers and cQunselers with the information necessary to classify workers and jobs appropriately in order to match them. The fourth edition DOT reflects the continued primacy of job-worker matching as the reason for its existence. The first sentence of its 196

The Classification of Occupations 197 introduction lists job matching as the primary justification for producing the DOT (p. xiii): The Dictionary of Occupational Titles is an outgrowth of the needs of the public employment service system for a comprehensive body of standardized occupational information for purposes of job placement, employment counseling and occupa- tional and career guidance, and for labor market information services. In order to implement effectively its primary assignment of matching jobs and workers, the public employment service system requires a uniform occupational language for use in all its offices. This is needed to compare and match the specifications of employer job openings and the qualifications of applicants who are seeking jobs through its facilities. CREATING OCCUPATIONAL TITLES The process by which the millions of jobs in the economy are grouped into the occupational titles in the DOT iS crucial in determining the usefulness of the DOT as a matching tool. The fourth edition DOT describes this process in general terms (p. xv): Work is organized in a variety of ways. As a result of technological, economic and sociological influences, nearly every job in the economy is performed slightly differently from any other job. Every job is also similar to a number of other jobs. In order to look at the millions of jobs in the U.S. economy in an organized way, the DOT groups jobs into "occupations" based on their similarities and defines the structure and content of all listed occupations. Occupational definitions are the result of comprehensive studies of how similar jobs are performed in establishments all over the nation and are composites of data collected from diverse sources. The term "occupation," as used in the DOT, refers to this collective description of a number of individual jobs performed, with minor vanations, in many establish- ments. The process of arriving at the 12,099 occupations defined in the fourth edition involves two steps, which are described in detail in chapters 6 and 7. First, on the basis of actual observation of workers in a number of positions, a job description is written by completion of a job analysis schedule. Then the job descriptions are grouped into occupations, and composite descriptions are prepared for inclusion in the DOT. Conceptual- ly, these two steps are similar; both "job" and "occupation" are theoretical entities. The central question in creating these entities is how to delineate the boundaries, by deciding how much heterogeneity should be tolerated within them. The same kind of question arises in the next step in the process: arranging the 12,099 occupational definitions into a classification struc- ture. The remainder of this chapter is devoted to this topic.

198 GROUPING OCCUPATIONS WORK, JOBS, AND OCCUPATIONS Traditionally, the Employment Service has used the occupational titles in the DOT in a relatively straightforward manner to match available jobs and workers. For example, those who indicate that they are plumbers (or have worked as plumbers) are matched with any openings for plumbers on file at the local Employment Service office. The matching procedures are relatively uncomplicated if there are job openings for plumbers (and if the plumber is satisfied with one or more of the available positions). A more difficult question arises when there are no openings in the occupation in which a worker is classified. In such instances the Employment Service either must send the worker away without offering him or her any opportunity for employment or must make fundamental decisions about the similarity of occupations and accurate estimates about the degree of transferability of the worker's skills and experience in past occupations to one or more alternative occupations. Interviewers appar- ently do this quite frequently. As we have already noted, assessing the transferability of skills goes beyond the paradigm for job-worker matching that originally motivated the DOT and was expressed in its first edition; the underlying principle is, however, extremely important. Workers typically can perform in many occupations besides the ones in which they have previously been employed; moreover, many skills are learned on the job. It may be that for a large number of jobs, previous work experience is more or less irrelevant. Among the 12,099 occupations described in the DOT we find a great many that appear to involve similar skills and aptitudes. For example, workers who have experience as a Landscape Laborer (408.687-014) may be reasonable referrals for occupa- tions such as Laborer, Brush Clearing (459.687-010) and Laborer, Golf Course (406.683-010~. We note, however, that these occupations are not grouped together in the DOT'S classification scheme. Since the DOT classification is used to organize files of job openings and applicants in local Employment Service office job banks, the location of occupations in the classification structure will effectively determine to which job openings a job seeker is exposed. This is particularly the case if the lists of job openings are extensive, as they are in large labor markets. The Landscape Laborer (408.687-014) mentioned above might have to search through listings for many jobs before coming upon an opening for a Laborer, Brush Clearing (459.687-010~. To the extent that any ordering scheme makes it easier to locate an appropriate job, it obviously increases the employment opportunities of workers, especially since (in the offices we visted) more than 70 percent of all Employment Service job referrals

The Classification of Occupations 199 are made by workers themselves finding appropriate job openings in the lists maintained by the employment office. It is simple to observe that a system that directs landscape laborers only to openings in that field and does not refer them to employment opportunities in related areas is overly restrictive. It is a far less simple matter to develop a general solution to this problem. The difficult question is how to decide, in general, what constitute reasonable occupational referrals. How does one decide what occupations are similar? How can one expand the employment opportunities of workers who seek work at the local Employment Service offices? Two plausible approaches to these questions are embodied in the classification structure of the fourth edition DOT. First, occupations are organized in groups essentially according to technologies; 559 of these occupational groups are represented by the first three digits of the DOT occupational code. Second, each occupation is also characterized by the requirements it places on workers in terms of their interaction with data, people, and things; these requirements are represented by the second three digits of the code. Either set (or both sets together) of digits could be viewed as a reasonable index of the similarity of occupations, although it is important to note that neither has ever been validated against an external standard. In the fourth edition the occupational titles and their definitions appear in order according to the numerical DOT codes. This ordering means that the technologically defined groups have precedence in the classification system over the worker function groups. The DOT Code: The First Three Digits The occupational groups represented by the first three digits of the code appear to have been developed in an ad hoc manner by considering a composite of industry; work field; machines, tools, equipment, and work aids (MTEWA);i and materials, products, subject matter, and services (MPSMS). (See chapter 6 and U.S. Department of Labor (1972:5-7) for a detailed discussion of these concepts.) In assigning the first three digits to an occupation, the job analyst or the definition writer is instructed to consult the DOT'S existing classification, particularly the narrative descrip- tions of the major categories and divisions, in order to identify in which of the 559 occupational groups the occupation belongs. This process involves iIn the work field "logging," for example, the following descriptions of tasks are suggested: "Climbs tree, using climbing spurs and safety rope, and cuts limbs, knots, and top from tree with ax and handsaw" (U.S. Department of Labor, 1972:89).

200 WORK, JOBS, AND OCCUPATIONS a good deal of judgment, since some of the categories are very similar. In the absence of more specific guidelines, the DOT code may be assigned in a somewhat arbitrary manner. Moreover, reliance on the existing clas- sification of the third edition DOT as the bench mark for the assignment of category codes in the fourth edition undoubtedly discouraged rearrange- ments of the classification and changes in codes. While definition writers for the fourth edition could in principle recommend that categories be combined or eliminated or that new ones be created, there is no documentation of such recommendations. The DOT Code: The Second Three Digits The third edition DOT and various trial matching programs used the worker function scales (the second three digits of the DOT code) to identify occupational groups,2 but the fourth edition makes no attempt to do so. Attempts to classify occupations solely on the basis of their complexity in relation to data, people, and things have been generally unsuccessful. An automated matching system based on worker function codes did not work out, nor did a manual matching attempt in Pittsburgh during the experimental period prior to publication of the third edition.3 Despite the failure of the worker function scales to serve as an adequate basis for matching, the concept is probably useful in developing a classification system for matching. The worker functions are intended to summarize characteristics of workers required by the job (such as their interests and aptitudes).4 They were developed from a realization that every job is actually a job-worker situation and that to describe such a situation adequately, knowledge of the characteristics of both the job and the worker is required. The worker traits required by a job are not 2The 22 major categories of the worker function scales, called areas of work, appear to have been developed in an ad hoc manner. Within each category, occupational groups of related worker function codes are created, but the correspondence of groups to codes is not unique. The same worker function code (e.g., .288) often appears in many different groups. This is perhaps not surprising, since worker function codes attempt to measure the complexity of the job and omit reference to specific skills, which are often important in placement. 3Interview, Adaline Padgett, occupational analyst, Division of Occupational Analysis, U.S. Employment Service, August 1979. 4In their description of the Functional Occupational Classification Project, Fine and Heinz (1958) recount the process by which all the occupational measures created for a group of 4,000 experimental occupations were used as bases for sorting the data into groups of similar occupations; they concluded that the worker functions form the best groups because the profile of the occupations on all the other variables was fairly consistent within worker function groups, at least more so than for groups formed on other bases. It should be pointed out that the techniques for discerning common patterns in data have advanced significantly since the mid-1950s when this research was done. Fine and Heinz sorted the data repeatedly in a search for consistent patterns.

The Classification of Occupations 201 captured by the considerations that currently enter into determining the first three digits of the DOT codes, which appear to be based primarily on technological processes. Summary Because the transferability of skills is generally regarded as the most appropriate criterion for assessing the similarity of occupations with a view to matching jobs and workers, the two aspects of the classification structure inherent in the DOT codes (the first and second sets of three digits) were ostensibly designed to capture two important elements of the transferability of skills. The first element is job-specific knowledge or skills the technological aspects of the occupation, the particular subject matter, and the materials and equipment used. These are described by the first three digits of the DOT code. The second element involves the qualities of workers that are required by jobs. These are thought to be captured by the worker function codes (the second three digits) because the worker function configurations "profile" a variety of worker traits consistently. These two bases of classification of the occupational titles in the DOT are conceptually quite appropriate in the judgment of the committee. The implementation of these concepts in practice, however, appears to be somewhat inadequate, and it remains an open question whether these two elements of the transferability of skills could not be better tapped by indicators based on other methodologies. THE KEYWORD SYSTEM OF THE EMPLOYMENT SERVICE More an alternative mechanism for matching job applicants with job openings than an alternative classification system, an automated keyword system has been implemented in a number of Employment Service offices throughout the country. This system was the subject of a limited staff review, reported in Appendix G. The main conclusion that should be drawn from this review is that although automation of the matching process is highly desirable, the keyword system as it is currently implemented suffers severe difficulties and needs to be thoroughly reviewed by a committee of experts, a task that goes beyond the charge to our committee. EXISTING ALTERNATIVE CLASSIFICATIONS FOR JOB WORKER MATCHING Several alternative methodologies for constructing occupational clas- sifications have been developed in recent years. The task inventories and

202 WORK, JOBS, AND OCCUPATIONS the Position Analysis Questionnaire (PAQ) techniques described below may be especially useful in identifying the types of skill components involved in particular tasks and jobs. The identification, measurement, and clas- sification of skills is at the heart of the problem of personjob matching. With a thorough understanding of the skills required by a broad variety of jobs as well as sound measures of those skills, it might be possible to develop taxonomies of persons and occupations that would facilitate differential placement, counseling, guidance, and education (see Altman, 1976; Canada Employment and Immigration Commission, Occupational and Career Analysis and Development Branch, 1978; McKinlay, 1976~. The feasibility of developing classifications based on knowledge of skill content, at least in certain fields of work, is illustrated by descriptions of certain military occupations (Morsh, 1966~. The PAQ data for 746 jobs have been used to create job families based on worker-oriented dimensions of skill, omitting the technological aspects (Straw et al. (1977~; also see Colbert and Taylor (1978), Taylor (1978), and Taylor and Colbert (1978~. Another inventory, the Occupational Analysis Inventory, has been used to group 1,414 jobs into 21 clusters (Pass and Cunningham, 1976~. Classifications based on job dimensions derived from structured job analysis or task inventories, when combined with taxonomies of human performance (Fleishman, 1975), appear to provide another way to address directly the issue of the suitability of workers' skills, abilities, or other characteristics for specific categories of jobs. As Dunnette (1976:516) notes, there now exist several methods for describing or predicting how efficiently different persons may be expected to perform various work functions: Further research . . . should focus on developing . . . short, easily adminis- tered, and easily understood behavior description inventor~ies] which may be used as a common basis for classifying jobs, tasks, job dimensions, human attributes, aptitudes, skills, and tests and inventories into the same taxonomic system. Because of the level of detail involved in inventory approaches, research has been limited so far to a few work areas. Many more areas would have to be studied to make these techniques generally useful in developing classifications for personjob matching purposes. Despite this limitation the inventory approach is one that appears to be worth pursuing. Counseling psychologists have attempted to create classifications of workers and jobs of the sort suggested by Dunnette. The resulting systems for personjob matching do not involve as much detail as do the task inventory approaches and are also more indirect, usually relying on the characteristics of persons rather than the characteristics of the work itself for the development of the matching scheme. Two attempts, the

The Classification of Occupations 203 Minnesota theory of work adjustment (Borgen et al., 1972; Dawis and Lofquist, 1974, 1975, 1976; Lofquist and Dawis, 1969; Rosen et al., 1972) and Holland's theory of careers (Holland, 1566, 1968, 1973a, 1976; J. Holland and G. Gottfredson, 1976; Holland et al., 1972) use classifications of occupations to explain vocational adjustment and vocational choice, respectively. These two schemes are of interest for three reasons: First, both theories have developed occupational classifications for the specific purpose of matching workers with jobs. Second, both theories incorporate independent but parallel classifications (Holland) or characteristics (Minnesota) of persons and occupations and explicit procedures for specifying the degree of match between a person and a number of occupations. Third, both perspectives have generated substantial re- search.5 MINNESOTA THEORY OF WORK ADJUSTMENT According to the Minnesota theory, the greater the correspondence between a person's abilities and the patterns of aptitudes required by a job, the better his or her performance (satisfactoriness) and the greater his or her persistence in the job. Similarly, correspondence between a person's "needs" (values, interests) and patterns of occupational reinforcers leads, according to the theory, to job satisfaction and persistence. Recently, Dawis and Lofquist (1974, 1975) have also used occupational aptitude pattern clusters and occupational reinforcer pattern clusters to form a classification of occupations and have shown how this classification is related to the DOT and Holland classifications. In general, the evidence about the usefulness of the Minnesota theory implies moderate support for the theory and its associated tools (Betz et al., 1966; Elizur and Teiner, 1977; Weiss et al., 1965, 1966~. The theory predicts satisfaction more efficiently than performance, and researchers have found relatively stable differences among occupations in their patterns of reinforcers and aptitude requirements. It is also clear that predictions of performance (satisfactoriness, satisfaction, and persistence) are relatively inefficient, even with the aid of this elaborate and carefully constructed set of tools for personjob matching. These relatively weak predictions of important job-related criteria are not, however, limited to this particular theory. In this area of research, strong statistical associa- tions between predictors and criteria are rare (Dunnette, 1976; Ghiselli, 1973; Schletzer, 1966~. 5For reviews, summaries, critiques, and important tests, see Osipow (1973), Walsh (1973), McCormick (1979), McKinlay (1976), L. Gottfredson (1978), and Rounds et al. (1978).

204 WORK, JOBS, AND OCCUPATIONS The major limitations of the Minnesota theory are twofold. First, it relies on a number of indirect approaches to the determination of job characteristics, inferring them, for example, from employee or supervisor ratings or from the characteristics (especially abilities) of workers who are employed in an occupation. Second, the range of occupations for which occupational reinforcers and aptitude patterns are available is currently limited; data for only 148 occupations are available. Nevertheless, the Minnesota work demonstrates that, in principle, it is possible to engineer the independent assessment of persons and jobs in parallel ways so that the degree of workerjob match can be estimated. Such an approach could prove effective in capturing the two elements of skill transferability noted above, particularly the qualities of workers that are required by jobs. HOLLAND CLASSIFICATION OF CAREERS The second counseling approach to personjob matching is illustrated by Holland's (1973a) theory of careers. Holland has developed a typology of persons and occupations that includes six types: realistic, investigative, artistic, social, enterprising, and conventional. Inventories such as the Vocational Preference Inventory (Holland, 1978), the Self-Directed Search (Holland, 1973b), the Strong-Campbell Interest Inventory (Campbell, 1977), or 1'Inventoire Personnel (DuPont, 1979) are used to locate individuals in this topology, and, in turn, the modal characteristic of incumbents in a particular occupation is used to characterize that occupation.6 For counseling purposes, matches are made between the personalities of individuals and this characterization of occupations. Underlying the Holland classification is the notion that vocational choices are expressions of personality; thus there should be greater similarity between the personalities of incumbents of the same occupation than between incumbents of different occupations. Personjob congruence is said to exist when the personality type that a person most resembles accords with the category into which a given occupation falls. Congruence leads, according to the theory, to satisfaction, success, and stability or tenure in an occupation. 6Often, when data on profiles of job incumbents are unavailable, Holland and his colleagues resort to indirect approximations involving a substantial degree of judgment in classifying occupations. Use has been made of Strong Vocational Interest Blank data, Ruder Preference Inventory data, PAQ data, and observations of regularities between the Holland occupational classification and the DOT classification (Holland, 1973a; Holland et al., 1972). Approxima- tion techniques exist for assigning a Holland category to all 1960 and 1970 census occupations (L. Gottfredson and V. Brown, 1978) and to all third edition DoT.titles (Viernstein, 1972).

The Classification of Occupations 20S Tests of Holland's theoretical formulations have had mixed results. On one hand, despite the amount of subjective judgment involved in the classification of occupations, the occupational classification shows strong relationships of expected kinds with the Minnesota occupational reinforcer scales; the DOT worker functions, svP, and GED ratings; self-direction; and prestige (L. Gottfredson, 1978; Rounds et al., 1978~. The Holland occupational classification has also been shown to be efficient in organizing occupational mobility data in that the category of a worker's later job is substantially predictable from knowledge of the category of a worker's earlier job for those who change jobs (G. Gottfredson, 1977; Holland et al., 1973; Nafziger et al., 1974~. Finally, evidence verifying the dimensions of vocational interests that underlie Holland's classification of persons implies that his groupings are reasonably sound (Guilford et al., 1954; Hanson and Cole, 1973; Nafziger and Helms, 1974~. On the other hand, the classification appears to be most useful when it is supplemented by a general measure of occupational level such as the GED. It focuses primarily on occupational preferences, and the measurement of occupations is indirect. The occupational classification resembles in some ways the approach to development of the Occupational Ability Patterns of Dvorak (1935) and Patterson and Darley (1936) during the depression, paying little direct attention to the details of the work performed or the skills required to perform them. Also, it organizes occupational mobility and congruence data better for older than for younger people (G. Gottfredson, 1977; L. Gottfredson, 1979~.7 Variation in the methods used to classify occupations or persons results in slightly different classifications ("identifications" in Sokal's (1974) terms). Moreover, Holland's theory is incomplete with respect to the roles played by social class, intelligence, and special aptitudes in the allocation of persons to jobs. The theory incorporates a number of secondary propositions about the degree of congruence among the personality and occupational types that have not been discussed here (see Holland, 1973a). In general, the research tests of these secondary propositions have yielded weak support (G. Gottfredson, 1977; Nafziger et al., 1974; Rounds et al., 1978~. The proposition that congruence leads to success in an occupation is largely untested, and the evidence that congruence leads to job satisfaction is very weak (see the studies cited by Rounds et al. (1978~. Perhaps this reflects the fact that individual traits change over time as a result of occupational experience, in such a way as to create greater conformity between individual and occupational characteristics (Kohn and Schooler, 1973).

206 SUMMARY WORK, JOBS, AND OCCUPATIONS In short, the Holland and Minnesota approaches to personjob matching illustrate the value of independent but parallel assessments of persons and jobs and of the resulting occupational classifications, but both approaches employ limited mechanisms for the assessment of actual job content and skill requirements. An approach to occupational classification that seeks a middle ground between the extreme specificity of task analysis and the detailed examination of human abilities exemplified by Fleishman's (1975) work, on one hand, and the more global but indirect approaches to the parallel classification of persons and jobs illustrated by the Holland and Minnesota schemes, on the other, may be a fruitful approach to the improvement of the classification of occupations for the purpose of matching workers and jobs. A MOBILITY-BASED APPROACH TO JOB-WORKER MATCHING The transferability of skills between occupations should be the primary basis for classifications whose purpose is job-worker matching. The mobility that occurs in the labor market, specifically the changes between occupations that workers sometimes make when they change jobs, provides one indicator of the transferability of skills between occupations. If workers move frequently back and forth between a pair of occupations, we can infer that the occupations require similar aptitudes and skills, or at least that those who perform one occupation are generally capable of performing the other; otherwise, transfers would not occur.8 Clas- sifications that have been developed for the purpose of job-worker matching should group together those occupations among which workers commonly transfer. As we have seen, in the DOT classification many jobs that appear to require similar skills are placed in widely different occupational categories. For example, Dispatcher, Radio (379.362-010) is classified as a protective service occupation, while Dispatcher, Traffic or System (919.162-010), which involves essentially the same skills, is classified as a miscellaneous transportation occupation. Similarly, Engrav- er, Hand, Hard Metals (704.381-026) is classified as a benchwork ~Obviously, one-way transfers must be treated more cautiously, since they may represent promotion ladders. It would not be desirable, for example, to send an assembly line worker to an opening for foreman even though foremen are almost entirely drawn from the ranks of line workers. In practice, however, this is not much of a problem, since supervisory personnel are almost always promoted from within. See Appendix H for a discussion of ways to use unidirectional transfers to infer career ladders.

The Classification of Occupations 207 occupation, while Die Maker (979.281-010), which involves similar tasks, is classified as a miscellaneous occupation. Naturally occuring mobility between occupations' categories is a sufficient but not necessary indicator of the transferability of skills. There are many jobs between which mobility does not occur despite similarity in content, because of custom, discrimination, or other reasons (McKinley, 1976~. For example, women who are secretaries move into managerial jobs only rarely, primarily because of tradition and prejudice, even though secretarial skills such as planning and coordinating may be highly relevant to many managerial jobs. Hence it would be unwise to rely on mobility patterns as the only or even the primary basis for assessing occupational similarity. However, a mobility approach may provide a useful supplement to traditional methods of assessing the similarity of occupations and the transferability of workers, by providing an empirical criterion for judging the similarity of occupations and the substitutability of labor.9 Whereas the classifications we have reviewed above rely mainly on analysts' judgments regarding the similarity of jobs, in the mobility approach, occupations are grouped solely because of high degrees of movement between them. The nature of occupations need not be analyzed in order to identify similarities to be used as a basis for classification; it is necessary only to locate movement among occupations, whatever their nature. (The mobility approach must, however, rely on other approaches to define the basic occupations; 100 million positions in the economy must first be classified into a reasonable number of occupational titles before movement between occupations can be assessed.) In this section we describe the potential of mobility data as a basis for constructing classifications and enumerate the advantages and disadvantages of this approach. We have undertaken some exploratory analyses to assess the feasibility of developing alternative classifications based on the available job mobility data. Basically, we attempted to group in clusters those jobs between which the rates of transfer were high. Technical details of these analyses are provided in Appendix H; for similar work, see Dauffenbach (1973~. Our analyses have led us to several general conclusions: 1. Mobility data can be useful for constructing an occupational classification that is useful for placement, but the basic occupational titles for which mobility data are collected must be defined by other procedures. Occupational mobility data can contribute little to the definition of 9See Roe et al. (1966) and Holland et al. (1973) for earlier studies of classifications using mobility data.

208 WORK, JOBS, AND OCCUPATIONS occupations as clusters of similar jobs. For this work other methodologies such as job analysis or task analysis are required. 2. Some plausible statistical models for transfers are available and can be used as a guide in evaluating and generating classifications and career ladder orderings. 3. It is technically feasible to construct occupational categories so that most transfers take place within relatively small groups and according to career ladders. Computations for developing such a classification might cost several hundred thousand dollars if the full set of 12,099 DOT titles were used. New algorithms would have to be developed. 4. It is technically feasible to apply this kind of analysis to the job history data currently gathered from Employment Service clients, since these job histories are routinely assigned DOT codes.~° 5. Classifications based on observed transfers among occupations suggest hypotheses about how the observed mobility has come about. Independently generated data on task and skill similarities, and also on the social characteristics of incumbents of occupations (e.g., age, sex, and race), could be used in conjunction with data on mobility rates to further our understanding of how people move among jobs. 6. Because some transfers may be excluded (or included) for reasons other than those having to do with the transferability of skills, such classifications should not be used uncritically. It is necessary to examine the job content of the occupational categories suggested by the mobility- based clusters in order to include any additional potential transitions and in order to exclude absurd clusters created as artifacts of the statistical algorithm. ADVANTAGES AND DISADVANTAGES The mobility approach to developing placement-oriented classifications has several advantages. First, it can be developed from data already collected by the Employment Service, which in its day-to-day operations routinely collects work histories from applicants. For each local labor market and for the specific clientele they deal with, the Employment Service collects all the data needed to find out what occupational linkages commonly occur. Second, the mobility approach allows for great flexibility and continuous improvement. Since the underlying mobility matrices can be continuously updated by using data from the ordinary operations of the Employment Service, classifications for matching can be altered as labor i°To be useful, these data would have to be preserved as a nine-digit occupational code. At present, the third through ninth digits are discarded when the interview data are keypunched.

The Classification of Occupations 209 market conditions change. For example, by using regularly updated transition matrices for a local labor market, the procedure could reflect the fact that the opening of a new automobile assembly plant had created new employment opportunities for workers formerly employed as coal miners. Third, this method avoids the ad hoc judgments of program designers, occupational analysts, or vocational counselors in deciding what are similar and dissimilar occupations for the purpose of job referral; it relies instead on the actual experiences of workers as they test various alternatives in the labor market. Fourth, the approach would overcome problems inherent in the overly narrow occupational classifications of the DOT, since all occupations between which workers routinely transfer would be grouped together. The mobility approach, however, is not without its disadvantages. First, as noted earlier, the resulting categories will reflect in part the current practices of employers rather than the potential possibilities for transfer inherent in the nature of transferable skills among occupations. Employers may perpetuate, even unwittingly, discriminatory or stereotyped hiring practices, or they may fail to perceive the potential of workers to move into new occupations. To the extent that this occurs, the use of a classification based on actual transitions will continue to perpetuate these undesirable limitations on workers' employment opportunities. Second, and analogous to the first disadvantage, the resulting classification will reflect in part the current preferences and possibly limited horizons of job seekers themselves. Such a classification might not expose workers to what has not been tried before. Third, if the resultant groupings are based on data generated by Employment Service activity, they will rehect in part the practices of the Employment Service itself. When workers with particular occupational histories are referred most often to job openings in certain other occupations on the basis of currently used classificatory practices, these patterns in referral practices will naturally tend to appear also in data on placements. Fourth, the reliance on job histories to provide mobility data may result in classifications that meet the needs of new entrants and labor market reentrants inadequately. Fifth, regularities in occupational transfers per se may tell us little about the desirability of the transfers from the point of view of either the employer or the employee. Placements may differ in terms of stability or tenure of employment, productivity or performance, and employee satisfaction or employer perceptions of satisfactoriness. Classifications based on mobility data may group together, then, placements of differing usefulness; such clas- sifications do not provide information on the likely quality of the matches, though labor market information (such as job tenure) could be used to supplement the classification.

210 WORK, JOBS, AND OCCUPATIONS STRATEGIES FOR IMPROVING OCCUPATIONAL CLASSIFICATION FOR JOB-WORKER MATCHING These disadvantages suggest that the mobility approach to developing placement classifications must be supplemented by other information. First, and most crucial, a reliable set of occupational definitions is necessary to provide the data base for mobility studies. Job analyses, then, must continue to be the basic building materials of classification systems. Second, because of current limitations on labor market mobility, addition- al indicators of the transferability of skills must be developed in order to encourage employers, workers, and the Employment Service to try new types of matches. Again, job analysis approaches are appropriate, as are vocational counseling approaches. Moreover, mobility patterns might be studied to identify groups of occupations for which specialized approaches such as task analysis would be particularly useful. Third, because without supplemental information the mobility approach treats all matches as being equally good, additional information about the quality of the matches must be developed. There are two plausible approaches to developing this information. The quality of the match could be inferred from labor market data on, for example, the average job tenure of particular types of matches (e.g., coal miners in steel mills), or the quality of matches could be assessed by directly querying workers and employers. Either approach could contribute to improving the quality as well as the quantity of matches. Fourth, mobility data must be supplemented by information about new entrants and returning workers. Direct skill and ability assessment will continue to be useful in developing placement possibilities, not only for those with limited labor market experience but also for those workers who want to change careers. OTHER METHODOLOGIES Among the other alternative methodologies that may provide independent assessments of occupational similarity, a prime candidate is task analysis (including task inventories and position analysis questionnaires). Similar in many respects to traditional job analysis, task analysis aims to describe occupations in terms of the types of job tasks that are performed. It differs from job analysis in both the explicitness of its attempt to assess the similarity of occupations and its method of measurement. Task analysis has been extensively used by the military services and to a lesser extent by other government agencies such as the Public Health Service. By using data rating the extent to which various jobs involve a common set of tasks, it is possible to apply clustering and scaling procedures to construct a

The Classic cation of Occupations 211 simplified description of the similarity of these jobs. The resultant description may be used to construct a classification of jobs in which similarity is taken to mean similarity in task content. This procedure could provide an alternative perspective to the mobility approach to the similarity of occupations. Worker characteristics can also be used to assess the similarity of occupations. As we note above, classification systems developed by Holland in his theory of careers or in the Minnesota theory of work adjustment tap important dimensions of occupational similarity. More- over, the techniques developed by vocational counselors to assess the quality of matches from the point of view of both workers and employers provide useful tools to assess the success of various classification schemes in generating appropriate placements. These techniques are also useful in providing knowledge of the skills, abilities, and aptitudes of workers that supplement knowledge gained from job histories; they will thus be particularly important for new entrants, reentrants, and those wishing to explore different areas of work. Classifications that are truly ideal for placement must make use of a variety of approaches. Further research on developing classifications for job-worker matching is particularly necessary along two lines. First, the use of mobility data to indicate the transferability of skills and to locate plausible job-worker matches should be investigated further. Second, methods for assessing worker characteristics, such as skills, aptitudes, and interests, and indicators of the adequacy of matches, such as satisfaction, performance, and persistence, should be investigated. A RESEARCH PROGRAM FOR DEVELOPING CLASSIFICATIONS A research program intended to develop or improve classifications for placement purposes might evaluate several aspects of the resulting classifications: 1. What heuristic value do the classifications have for contributing to an understanding of the transferability of skills, barriers to labor market mobility, or the segmentation or Balkanization of labor markets in both desirable or undesirable ways? 2. How successful are the classifications in generating satisfactory placements? What proportion of job referrals made using a classification or matching scheme results in placements (i.e., employer decisions to hire and applicant decisions to accept employment)? How long do the placements last? Do persons referred to jobs continue working at those jobs for an acceptably long period of time? Put another way, do alternative matching

212 WORK, JOBS, AND OCCUPATIONS procedures make any difference for the employment stability of users of the Employment Service? 3. What are the long-range outcomes of placements made in terms of the income, job satisfaction, and performance of the persons placed? 4. How easy is it for employment interviewers, applicants, and employers to understand and use each system? 5. Are different classifications useful for different aspects of job-worker matching? CONCLUSION In this chapter we have reviewed the classification structure of the DOT as well as alternative bases for systems of occupational classification and have raised some of the conceptual issues involved in developing classifications for job-worker matching, in particular the notion of occupational similarity and the transferability of skills. We have suggested the use of data on naturally occurring patterns of labor mobility to evaluate, refine, and develop new occupational classifications. Our analyses lead us to conclude that mobility-based methods may provide a flexible methodology for evaluating and developing classification systems for use in placement. They have the unique advantage of using the actual histories of workers in the labor force as guides for defining what are appropriate (and inappropriate) matches to make for individuals with a given occupational background. This method avoids ad hoc judgments and permits greater flexibility than previous centralized, once-a-decade exer- cises in occupational grouping. Nonetheless, our work also indicates a clear need for more traditional occupational analysis procedures. At a minimum, such procedures are needed to define the basic occupational titles. There are, however, other important reasons for shunning excessive reliance on mobility data in making placement decisions. Any history of occupational mobility reflects not only the potential range of the transferability of workers' skills between various occupations but also the patterns of discrimination in hiring and promotion that now exist (or previously existed) in the labor market. So, for example, the fact that administrative secretaries do not commonly advance into management occupations may reflect patterns of sex discrimination in hiring and promotion rather than any inherent lack of transferability of their skills. Any placement system guided exclusively by the history of labor mobility between occupations would build the past biases of the market into its future operations. These considerations dictate that any mobility-based approach to describing the similarity of occupations should be supplemented by other

The Classification of Occupations 213 methods that do not depend on the past functioning of the labor market. An independent perspective on the similarity of occupations is required. Traditional occupational analysis procedures might play this role, al- though job analysis as currently practiced in the occupational analysis program has not been especially successful in defining the similarities of disparate occupations. In an approach that emphasizes required worker characteristics, the most ambitious attack on this problem has been the ratings measuring the complexity of a job in relation to data, people, and things of the occupational analysis program's functional job analysis approach. The validity of these ratings has not been studied systematically, however, and their relationship to the potential transferability of workers from one occupation to another remains to be shown. Moreover, as chapter 7 indicates, the reliability of these measurements is questionable. Any attempt to apply these particular measures as independent indicators of occupational similarity should be grounded in future studies of their criterion-related validity and ongoing quality control of their measure- ment. Other alternative methodologies that should be explored are task analysis or other forms of structured job analysis and personjob matches based on vocational preference theories such as that of Holland. The integration of (1) task analysis data obtained from representative samples of workers, (2) direct observation of jobs using more traditional job analysis procedures and the judgments of trained analysts, and (3) the assessment of workers' traits and personjob matches using techniques developed by vocational counselors, with (4) study of the naturally occurring patterns of labor mobility would provide a more adequate basis for developing classification systems and operational procedures for use by the Employment Service in matching jobs and workers. Criterion validity could be demonstrated by showing the relationship, if any, between the ratings of occupations on DATA, PEOPLE, and THINGS variables and the ease with which workers transfer between jobs in these occupations

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Work, Jobs, and Occupations: A Critical Review of the Dictionary of Occupational Titles Get This Book
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Various editions of the Dictionary of Occupational Titles have served as the Employment Service's basic tool for matching workers and jobs. The Dictionary of Occupational Titles has also played an important role in establishing skill and training requirements and developing Employment Service testing batteries for specific occupations. However, the role of the Dictionary of Occupational Titles has been called into question as a result of planned changes in the operation of the Employment Service.

A plan to automate the operations of Employment Service offices using a descriptive system of occupational keywords rather than occupational titles has led to a claim that a dictionary of occupational titles and the occupational research program that produces it are outmoded. Since the automated keyword system does not rely explicitly on defined occupational titles, it is claimed that the new system would reduce costs by eliminating the need for a research program to supply the occupational definitions.

In light of these considerations, the present volume evaluates the future need for the Dictionary of Occupational Titles.

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