The primary thrust of this study involved the efforts to analyze differences in classroom routines and to determine the degree of change between the commonly accepted routines of the regular teacher and the substitute replacement. The study was designed to systematically determine the teaching routines of fifteen secondary classroom teachers and the teaching routines of the fifteen substitute teachers which replaced them during a one-day absence. The observed differences in routine were also compared with the perception of students affected under the two sets of conditions. The research design for this study was developed as a descriptive field study. The basic research instruments were derived from the personal and professional experience of the researcher, a review of literature in the areas of evaluation, teacher effectiveness, and studies pertaining to substitute teachers. The instruments were designed or selected to elicit data concerning regular and substitute teaching routines in the following areas: (1) classroom interaction (Flanders Interaction Analysis), (2) classroom climate (Withall Climate Index), (3) teaching process (Standards of Quality for Virginia Public Schools, 1974), (4) teaching product (researcher), (5) student perception (researcher). The research instruments used in this study were scored by trained observers (Process, Product, Interaction, Climate) and students (Perception) during observational visits to fifteen secondary school classroom environments with a nonrandom fixed rule for selection. No generalizations of the findings were made; therefore, the study has the limitation that its findings are useful only as description and beginning insights to future hypothesis development. The first of two major statistical analyses employed in the study consisted of a BMD02R stepwise regression analysis performed to compare the data collected by observers regarding classroom routine with the student perceptions of substitute teachers. The second analysis performed was a BMD07M stepwise discriminant analysis for the purpose of determining the exact amount and kind of differences between the regular teacher's routine and that of the substitute teacher counterpart. The results of the study suggested that, according to students, substitute teachers accomplished only about one-half of what the regular teacher accomplished. Students also reported that their substitute teacher was not as "good" a teacher as their regular teacher. Further results revealed that there was a marked difference between eleven classroom routines of the fifteen under study when substitute teachers replaced regular teachers. This study represented an effort to systematically assess the differences in classroom routine of regular and substitute teachers, which to date has been neglected. The researcher views the availability of this type of data as essential to the efforts of those teachers and administrators involved in trying to improve the effectiveness of the substitute teaching service. / Ed. D.