PREP was originally designed to be used with students in Grades 2 or 3. In the present study, summarized here, eight tasks from PREP were selected and adapted for the Grade 1 level.
Das, Mishra, and Pool (1995) used PREP with a group of 51 Grades 3 and 4 students with reading disabilities, who exhibited delays of at least 12 months on either the Word Identification or Word Attack subtest of the Woodcock Reading Mastery Test-Revised (WRMT-R). Participants were first divided into two groups—PREP remediation and a no-intervention control group.
The PREP group received 15 sessions of training, in teams of two students each, over a period of two-and-a-half months. Children in the control group participated in regular classroom activities. After the intervention, both groups were tested again, using the Word Identification and Word Attack subtests. The results indicated that while both groups gained during the intervention period, the PREP group gained significantly more on both Word Identification and Word Attack subtests.
Carlson and Das (1997) report on two studies using a small-group version of the PREP for underachieving Grade 4 students in Chapter 1 programs. (Chapter 1 is a classification used in California for poor readers who have no mental retardation.) In the first study, the experimental group received 15 hours of “add-on” training with PREP, over an eight-week period. Both the PREP and control groups (22 and 15 students, respectively) continued to participate in the regular Chapter 1 program.
Word Attack and Word Identification subtests of the WRMT-R were administered at the beginning and the end of the study. The results showed significant improvement after training in PREP as well as significant group-time interaction effects. The second study essentially replicated these results with a larger sample of Grade 4 students. Since then, several other replication studies completed in the same school district have essentially reproduced the original results with children from Grades 3, 4, 5, and 6, and with both bilingual (Spanish-English) and monolingual (English) children.
The effectiveness of a modified PREP (for an older group) was studied by Boden and Kirby (1995). A group of Grades 5 and 6 students, who were identified a year earlier as poor readers, were randomly assigned to either a control or an experimental group. The control group received regular classroom instruction and the experimental group received PREP, in teams of four students, for approximately 14 hours. As in previous studies, the results showed differences between the control and PREP groups on the Word Identification and Word Attack subtests.
In relation to the previous year’s reading scores, the PREP group performed significantly better than the control group. Finally, the study by Parrila, Das, Kendrick, Papadopoulos, and Kirby (1999) is an extension of the these experiments but with three important changes: (a) the control condition was a competing program given to a carefully matched group of children; (b) the participants were beginning readers in Grade 1 and therefore younger than the Grade 3 to Grade 6 participants in the previous studies; and (c) the training was shorter in duration than most of the previous studies. The more stringent control condition was seen as an important test of the efficacy of PREP. The study attempts to demonstrate the efficacy of PREP by showing its advantage over a meaning-based reading program received by the control group.
Fifty-eight Grade 1 children experiencing reading difficulties were divided into two matched remediation groups—PREP and meaning-based. Results showed a significant improvement in reading ability (Word identification and Word Attack) for the PREP group, and the gain was larger than it was for the meaning-based training group. Relevance of the children’s CAS profile was demonstrated as follows. Further results indicated that the high gainers in the PREP group were those with a higher level of successive processing at the beginning of the program. In contrast, high gainers in the meaning-based program were characterized by a higher level of planning.
Taken together, these studies make a clear case for the effectiveness of PREP in remediating deficient reading skills during the elementary school years. The studies described indicate that word decoding improved after completion of PREP. These results suggest that PREP is effective with elementary school students who have reading and decoding problems that are related to successive processing difficulties. PREP’s success in Spain and South Africa also indicates that the program can be effectively adapted to various cultural contexts.