D. Finally there are cases in which tests having vocational significance have been sought by purely haphazard and empirical ways. Thus Lough, having devised a form of substitution test in which certain characters had always to be replaced by certain others, according to a prescribed key, then proceeded to apply it to groups of commercial students. Speed of improvement was chosen as the thing of interest in respect to the test. Measures of this capacity, as shown by repeated trials with the same test day after day, were then compared with measures of ability in different types of work in which the students were engaged. It was found that the test records agreed very closely with the abilities in typewriting, fairly closely with abilities in business correspondence and stenography, whereas there was not such definite relation found between the test records and ability in learning the German language or in mathematics. The test is consequently recommended as a useful means of detecting typewriting and stenographic ability. It is not pretended that the test is a miniature of the work of such calling, nor that it is a fair sample of such work, nor even that it involves precisely the same mental functions that come into play in such work. The test records and ability in the particular type of work show high positive correlation, which means that an individual who is good or medium or poor in the one is, as a mere matter of fact, also found to be good, medium or poor in the other. Hence, without further analysis, the one may be used as the sign of the other.
Another good illustration of the use of this method is the study of Lahy, who put good, average and poor typewriters through a great number of tests of different sorts. He found that the only tests correlating closely with ability in the practical work were those for memory span, tactile and muscular sensibility, sustained attention, and equality of strength in the two hands.
Perhaps the most perfect example of this purely empirical procedure is the investigation which has now been conducted for several years by Mrs. Woolley and her co-workers in Cincinnati. Children who leave the grades to enter directly into some sort of industrial occupation are examined by a miscellaneous assortment of simple mental tests. These records are preserved, and the subsequent successes or failures of the pupils in the various sorts of work undertaken by them in later life are as carefully recorded as is possible. It is hoped that when a sufficient amount of material of this nature has been accumulated the two sets of data may be compared and information thereby secured concerning the relation between ability in the tests and the types and degrees of industrial fitness. At present only the test records have been published.