meant to include all who graduate, either by diploma or by certificate. Any statement made in the following pages of 'time in school' or of time spent for 'securing graduation' will not include as a part of such period a semester in which the pupil is absent all or nearly all of the time, as in the case of absence due to illness. 5. THE SELECTION AND RELIABILITY OF THESE SOURCES OF DATA By employing data secured only from official school records and in the manner stated, this study has been limited to those schools that provide the cumulative pupil records, with continuity and completeness, for a sufficient period of years. Some schools had to be eliminated from consideration for our purposes because the cumulative records covered too brief a period of years. In other schools administrative changes had broken the continuity of the records, making them difficult to interpret or undependable for this study. The shortage of clerical help was the reason given in one school for completing only the records of the graduates. In addition to the requirements pertaining to records, only publicly administered and co-educational schools have been included among those whose records are used. It was also considered important to have schools representing the large as well as the small city on the list of those studied. Since many schools do not possess these important records, or do not recognize their value, it is quite probable that the conditions prescribed here tended to a selection of schools superior in reference to systematic procedure, definite standards, and stable organization, as compared to those in general which lack adequate records. The reliability and correctness of these records for the schools named are vouched for and verbally certified by the principals as the most dependable and in large part the only information of its kind in the possession of the schools. In each of these schools the principals have capable assistants who are charged with the keeping of the records, although they are aided at times by teachers or pupils who work under direction. In three of the larger schools a special secretary has full charge of the records, and is even expected to make suggestions for revisions and improvements of the forms and methods. In view of such facts it seems doubtful that one could anywhere find more dependable school records of this sort. It was true of one of the schools that the records previous to 1909 proved to be unreliable. There is no inclination here to deny the existence of defects and limitations to these records, but the intimate acquaintance resulting from close inquiry, involving nearly every factor which the records contain, is convincing that for these schools at least the records are highly dependable.