i8 EMPLOYMENT PSYCHOLOGY ical tests is quite in accord with the dictates of common sense and good practice. However, while similar in prin ciple, psychological tests differ from the general tests just mentioned in being far more refined and accurate. They are developed by a method based on very careful experiments and the use of accurate statistical formulas. The details of this method as applied to employment are explained in subsequent chapters. This method is gradually making it possible to obtain standard measures of the mental qualities, measures which are infinitely more accurate than those used in the past. By means of these measures or tests, it is becoming possible to set up standard specifications for the kinds of applicants who are desired for a given position, and to fill these specifications exactly as the tool maker would fill the specifications for a tool which he is to make. Not only will it be possible to apply these standards in the particular office or location where they have been origi nated, but it will be possible to apply them in all places. The psychological tests devised for use in the army, for instance, were distributed throughout every camp in the country, and as a result, the classification of all privates, commissioned and non-commissioned officers, was based largely upon standard measures. The distinguishing feature of employment psychology, that which differentiates it from applied psychology in general, is its field of activity. Heretofore mental tests have been devised largely in the university laboratory and have been tried out for the most part on students and pupils in educational institutions. Employment psychol ogy, however, works directly in the field of employment, not employment as represented merely by the activities of the employment office, but employment in the sense