To understand the implementation quality of the Tier 1 Program of the Project P.A.T.H.S., 25 schools and three school social service units were randomly selected to participate in telephone interviews regarding the quality of the implementation process of the Tier 1 Program of the P.A.T.H.S. Project. In the telephone interviews, the participants described the responses of the students and the workers to the program, the perceived benefits of the program, their assessment of the positive and negative features of the program, as well as difficulties involved in the implementation process. Results showed that most workers perceived that the students had positive responses to the program and half of the workers had positive experiences about the program, although negative comments on the program design and difficulties in the implementation were also recorded. Nearly all workers (97.1%) regarded the program to be beneficial to the students and most of them (78.6%) had positive global evaluation of the project. In short, while the program implementers expressed concerns about the program design and the implementation process, they generally regarded the program as helpful to the students and they had positive global evaluation of the program.