A statistical study of the PLTL Program in General Chemistry during the fall semesters of 2003 and 2004 demonstrated that PLTL participants performed about one-third of a grade-point higher than non-participants (earning a B versus a B- average). This benefit was found to be similar for all participants, regardless of their background characteristics (see section III.B.). Moreover, female students were more likely than male students to participate in PLTL, and minorities were about equally as likely as non-minorities to participate: 60% of the PLTL group members were female (compared to 49% of the students enrolled in the course), and 20% were minorities (compared to 18% in the course). Because female and minority students opted to participate in PLTL at rates equal or greater to their representation in General Chemistry, PLTL enhanced the learning of these two groups, both of which have been historically under-represented and under-prepared in science and mathematics.
The PLTL Program also provides opportunities for female and minority students to serve as leaders in these disciplines. Since 2002, 59 Peer Leaders (54%) have been female; 29 (27%) have been Asian, 17 (16%) have been African-American or Hispanic, and 4 (4%) have been Middle-Eastern. These Peer Leaders serve as role models who can inspire female and minority students in their PLTL groups to succeed and persist in science and mathematics.
 For example, an assessment at Washington University in fall 2002 showed that female and minority students were more likely than other students to be under-prepared for General Chemistry.