SELECTING MILTON M. MANDELL United States Civil Service Commission, Washington, D. C.
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scientific study of selection methods is approximately 30 years old in the United States. I n these 30 years, most of the studies have pertained to clerical, mechanical, and sales occupations. Only recently has interest been shown in the selection of professional employees. The most extensive work in the development of scientific selection methods for professional employees has been in the accounting field. The following report on the study of selection methods for chemists is based upon work done by the United States Civil Service Commission upon the recommendation of the President's Scientific Research Board in October, 1947. Approximately 150 chemists employed in the National Bureau of Standards and in the Eastern and Western Regional Research Laboratories of the Department of Agriculture were the subjects in this study. These chemists were in the first four grades of professional work in chemistry. The salaries of these grades are approximately $3000 to $6000 a year. A study of this nature usually involves three basic steps. The lirst step requires the identification of the occupational groups to be studied. I n the present study it was decided t o study positions in the iirst four grades, and chemists of all types, performing duties ranging from basic research to routine laboratory work. The next step involves a determination, usually based on job analyses, of the types of selection methods that should be included in the study. It was decided in the present instance to study primarily the value of various types of written tests for chemists. Mental ability, achievement, and spatial visualization tests, other types of written tests, and a biographical information blank were included. A third important step in studies of this kind is to determine the criterion t o be used. I n the case of this study three types of criteria were used. The first type involved a rating of job performance by the colleagues and superiors of the chemists included in this study, with the second type consisting of ratings on originality. The third criterion used was the salary level of the employee. In other words, an assumption was made that those a t higher salary levels, as a group, are superior to those a t lower salary levels, despite individual excePtions. It may be assumed that the individual excepL o hi^ study was carried on by the civil service commission as part of its regular program for the improvement of selection methods. Part of the work that was done on this project was ~erformedby persons employed by the American Council On Education in its contract with the Scientifio Personnel Division assumes of the oficeof Nw8] ~ ~ neither~ ~ ~ any responsibility for the contents of this report.
tion results in a n underestimate of the value of the selection methods rather than an overestimate, althobgh the effect of this element may vary with some tests. Fmally, by statistical means, the relationships between selection methods and criteria are correlated in order to determine which selection methods are most useful. This study furnished consistent evidence that a basic subject-matter test in the broad field of chemistry furnishes relatively accurate information in regard to the job performance of chemists. These data are consistent among the three laboratories. The test consisted of approximately 70 items and was prepssed by experts in the field of chemistry. As a result of this study, this test is being given substantial weight in the actual examinations being conducted by the United States Civil Service Commission for chemists. One example of the effectiveness of this test is provided by the data from the Eastern Regional Research Laboratory. Using salary as the criterion, approximately 80 per cent of those receiving high scores on the test were in the upper salary levels, while approximately 75 per cent of those receiving low grades on this test were in the lower salary level. This is contrary t o the usual asmmption that the higher the salary level of the chemist the more specialized his knowledge; with this assumption, the conclusion is reached that a test in the broad field of chemistry would be unfair. At least in the case of the present study, the data would indicate that those a t the higher salary levels know more about the general field of chemistry than those a t the lower salary levels. The data from the Western Regional Research Laboratory and the Bureau of Standards are consistent with the data from the Eastern Laboratory. the test results with overrn addition to of job and salary levels, correlaall tions were computed between test scores and the degree of originality of the subjects. For 75 cases, 17 of whom were chemists in the Bureau of Standards and 58 of whom were in the Eastern Laboratory, the Pearson moment correlations for the subject-matter test were the same, +0.46. Of the total grouE of chemists a t the Eastern Regional ~~~~~~~hLaboratory included in this study, 45 were engaged in basic research work. For this sample, the subject-matter test furnished a correlation of +0.61, using total job performance as the criterion. data indicate a relatively high consistAll Of the ency of value for this test for all three laboratories based on~ three criteria: ~ h . originality, salary level, and job performance in research work.
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SEPTEMBER, 1950
A test on ability to evaluate scientific hypothesesalso furnished significant results. This test was originally developed by Professor Max Engelhart of the Chicago City Junior Colleges. The Pearson product moment correlations between scores on the test and salary level for 65 chemists a t the Eastern Laboratory, 53 chemists a t the Western Laboratory, and 38 chemists a t the Bureau of Standards were +0.39, +0.44, and +0.41, respectively. Statistical tests of these data indicate that they are significant. I n addition, the hypothesis test also correlated significantly with ratings on originality. For 31 cases a t the Bureau of Standards the correlation with originality was +0.49, which is st* tistically significant. A test in the field of spatial visualization which is called surface development, and which involves the ability to visualize a two-dimensional object which is transferred t o a three-dimensional object, correlated with job performance but not with salary level, as might he expected from the nature of the test. For example, for 34 cases a t the Western Laboratory, twothirds of those receiving high test scores were in the upper half on job performance while approximately 75 per cent of those receiving low test scores were in the lower half of job performance. Using job performance as the criterion, for 30 chemists a t the Bureau of Standards, 30 chemists a t the Eastern Laboratory, and 33 chemists a t the Western Laboratory, the correlations for this test are +0.27, +0.36, +0.33, respectively. While these correlations are relatively lower than for the other tests, the surface development test would still be helpful in an examination because it measures abilities different from those measured by the subjectmatter and hypothesis tests; in other words, its intercorrelation with these tests is approximately zero based on a study of 56 chemists in the Eastern Regional Laboratory. A test of ability to translate a narrative statement into its mathematical equivalent, the formulation test, did not furnish significant correlations with job performance or salary level hut does seem to furnish significant information in differentiating between research and nonresearch chemists. For 26 chemists, 20 engaged in research work and six not engaged in research work, the difference in mean scores of the two groups was significantly higher in favor of the research chemists. The biographical information blank furnished much information regarding chemists. Following is a summary of the most interesting items. 1. Of the 58 chemists in the study who had not done any graduate work, 28 were rated high in job performance and 30 were rated low. Of the 34 Ph.D's in the study, 20 were rated high in job performance and 14 were rated low. 2. In answering the question, "Which one of the following characteristics of a job is most important to you?" a majority took the choice "working with competent people on a group solution of a problem." 3. A large proportion of the chemists in this study
had decided on their careers before the age of 18 with a substantial number deciding before the age of 16. 4. Of the 13 chemists who stated that the subject they did best in high school was either English or Social Science, only 2 of the 13 were rated high in job performance. 5. I n answer to the question, "Which one of the following things do you think you would most dislike about being a supervisor?" 19 of the chemists took the choice, "Don't like handling of personnel problems.:: Of these 19, 16 were rated high in job performance. Of the 14 chemists who took the choice in this question, "Too much responsibility," only 2 of the 14 were rated high in job performance. The most popular answer to this question was "Don't like the paper work involved." Fifty-seven chemists took this choice. 6. Fifty chemists in the group had graduated in the top ten per cent of their college class. Of these 50 chemists 27 were rated high in job performance and 23 were rated low in job performance. Of the 26 chemists who were in the second quarter of their college graduating classes, 12 were high in job performance. 7. Of the 43 chemists who had graduated from high school at the age of 16, 31 were high in job performance. Of the 33 chemists who had graduated from high school a t the age of 18 or later, only 11were rated high in job performance. 8. I n answer to the question, "Which one of the jobs below would he most interesting to you?" most of the chemists took the choice, "Working on a long range project even though significant results cannot be expected in a short period." 9. I n answer to the question, 'Which one of the jobs below would you find least interesting?" the favored answer was "Acting as administrative assistant to the head of a laboratory." 10. Of the 34 chemists who were members of scienti6c honorary fraternities 22 were rated high in job performance. Of the 31 chemists who were graduated with honors, 14 were rated high in job performance. 11. Of the 35 chemists who had no papers published in a scientific journal, 17 were rated high in job performance. Of the 50 chemists who have had four or more papers published, 28 were rated high in job performance. CONCLUSION
It is obvious that the above three studies are tentative in nature. Further research work will establish whether the tests reported above actually have validity beyond these three laboratories and will also help in providing information on the value of other types of selection methods. It is encouraging that tests of the simple type described above can furnish these relatively consistent and significant data. The United States Civil Service Commission intends to follow up the results obtained with this year's examination in order to obtain additional data on their value. I n addition, other selection methods will he experimented with to form a basis for continued progress in this field.
