PLTL is a model of collaborative learning that supplements large lecture courses, typically in science and mathematics. In PLTL, 6-8 students work together to solve problems in a study group facilitated by a Peer Leader. The course instructor designs the problems and supervises the Peer Leaders.
At Washington University, PLTL was introduced in General Chemistry in 2001 and has since been expanded to Calculus and General Physics. Research on PLTL at Washington University has contributed to a growing body of scholarship demonstrating its effectiveness in improving student learning.