Robert Koegel and Laura Schreibman developed PRT (Pivotal Response Training). It targets self-initiation of the subject’s preferred activities in a natural setting..
Fred S. Keller developed PSI (Personalized System of Instruction), a self-paced teaching method.
Ogden Lindsley developed precision teaching which uses a semi-logarithmic chart also known as a Standard Celeration Chart. The chart has a slope of 34 degrees.