Whether principals could identify teaching traits and categorize these consistently as descriptors of instructional stages was studied by asking 145 randomly selected principals in public schools throughout Illinois and Indiana to characterize teacher behavior based on experience. Principals were asked to list instructional stages, yielding 161 usable teaching characteristics. Another sample of 50 principals was then surveyed to derive, under principal component factor analysis, 5 factors appearing to fit the projected career development model. The sequential stages derived indicated that no age limit could be attached to the effectiveness cycle for a teacher. Appendices list variables for five different factors: (1) provisional stage; (2) development state; (3) decelerating stage; (4) stagnant stage; and (5) terminal stage. (SLD)