The final word on PSI is given to Fred Keller (1974b):
"...PSI is not for the teacher who feels he is currently successful, that age-old practices are basically sound or that any faults they have could be repaired with just a little effort. PSI is not for the teacher who is certain that all his problems would disappear if his students were more carefully selected, better trained before they reached him, or had sufficient pressure placed upon them to do the work they should. It is not for any teacher who believes that because he is a teacher the system that produced him must be mainly good; that teaching is a game that he must win in competition with his pupils; that lecturing is basic to every teacher's function; that an examination or quiz is way of weeding out the weaklings; that any large, strong, well-coordinated boy is probably a moron; that his course could be a measure of I.Q.; and that anyone who fails it is unlikely to succeed later in life." (p. 76)