To increase immunization coverage and prevent childhood illness, Indonesia has devolved responsibility for immunizations at the local level to health centers, appointed a practical nurse as immunizer in each health center, and developed a system of monthly visits (called Posyandu) to villages. The Maluku Ministry of Health and Project Concern International jointly undertook a series of activities to enhance the provincial immunization program, including field surveys, a computerized immunization information system, and an on-the-job peer-to-peer training program. The training program sent experienced, highly performing immunizers to the health centers staffed by inexperienced, poorly performing immunizers for 1 to 2 weeks to provide on-the-job training and assistance. District health officials selected both the trainee and the trainer immunizers, using information from the surveys and information system. An evaluation of the training program compared changes in key performance indicators in the year before and the year after the training between a group of 13 immunizers trained in 1993 and 1994 (program group) and a group of all 95 immunizers in the province who did not receive the training (nonprogram group). Coverage of DPT1, polio3, and measles vaccine in the program group rose about 40%, while coverage in the nonprogram group remained nearly constant over the 2-year period, a highly significant difference (p
