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Research
Eleven studies reviewed by the WWC investigated the effects of PALS. Four studies met WWC evidence standards with reservations. Two studies (Fuchs, Fuchs, Kazdan, & Allen, 1999; Mathes & Babyak, 2001) were randomized control trials with randomization problems, and two studies (Mathes, Howard, Allen, & Fuchs, 1998; Mathes, Torgesen, Clancy-Menchetti, Santi, Nicholas, Robinson, & Grek, 2003) were quasi-experimental designs. The remaining seven studies did not meet WWC evidence screens.
Met evidence standards with reservations
Fuchs et al. (1999) included 45 second- and third-grade students from 15 general education classrooms. Fuchs et al. compared two interventions—Peer-Assisted Learning Strategies and Peer-Assisted Learning Strategies plus Help Giving— to a comparison group that used the same curriculum as the intervention group but did not implement collaborative learning. Teachers were randomly assigned to the intervention or comparison group, but after random assignment, teachers selected three students with different achievement levels within each participating classroom to be part of the study. The WWC review of this study focused on the comparison of PALS and the comparison group with a total of 10 at-risk students in the second and third grades. 5
Mathes and Babyak (2001) included 110 first-grade students from five schools in a medium-sized school district in Florida. Mathes and Babyak compared two interventions— Peer-Assisted Learning Strategies and Peer-Assisted Learning Strategies plus Mini-Lessons— to a comparison group that used a typical reading curriculum with no supplement. Teachers were matched on demographic characteristics to form a stratified sample and randomly assigned to the intervention or comparison group, but after random assignment, teachers selected five students with different achievement levels within each participating classroom to be part of the study. 6
Mathes et al. (1998) included 96 first-grade students from six schools in an urban school district in the southeastern United States . Some teachers were randomly assigned to the treatment or comparison condition, but some were matched based on teaching profiles, generating a quasi-experimental study design. After teacher-level assignment, study authors selected five students with different achievement levels per classroom to be part of the study. The study compared PALS to a comparison group that used a typical reading curriculum with no supplement.
Mathes et al. (2003) included 89 low-achieving first-grade students taught by 22 teachers from six schools in a medium-sized southeastern school district. Some teachers were randomly assigned to the treatment or comparison condition, but some were matched based on teaching profiles, generating a quasiexperimental study design. After teacher-level assignment, study authors selected up to five low-achieving students per classroom to participate in the study. Mathes et al. compared PALS to a program similar to PALS but with teacher-directed instruction, and to a comparison group that participated in their usual reading curriculum.
Extent of evidence
The WWC categorizes the extent of evidence in each domain as small or medium to large (see the What Works Clearinghouse Extent of Evidence Categorization Scheme). The extent of evidence takes into account the number of studies and the total sample size across the studies that met WWC evidence standards with or without reservations. 7
The WWC considers the extent of evidence for PALS to be small for alphabetics, fluency, and comprehension. No studies that met WWC evidence standards with or without reservations addressed general reading achievement.
6 Findings for the comparison between PALS plus ML and the comparison groups are included in Appendices A4.1 and 4.2 but do not factor into the intervention rating.
7 The Extent of Evidence Categorization was developed to tell readers how much evidence was used to determine the intervention rating, focusing on the number and size of studies. Additional factors associated with a related concept, external validity, such as the students' demographics and the types of settings in which studies took place, are not taken into account for the categorization.
