This note describes the MIES that was designed for monitoring PHC performance. A study was carried out on the monthly performance of 80 PHCs in six districts in Uttar Pradesh. One significant factor influencing performance of a PHC was the quality and quantity of supervision by district authorities. On the basis of these findings a monitoring system was developed and implemented in six districts of Uttar Pradesh covering 88 PHCs. The new system had two immediate effects. It generated interest in evaluation among administrators and PHC doctors mainly because of its grading system. Second, the higher-level administrators were able to identify problem PHCs, not previously diagnosed. The feedback provided by the system only indicated the problem areas but the task of investigating the actual assignable causes was left to supervisors. Later, several diagnostic studies were carried out to identify some PHCs in which extraneous factors inhibited performance and the results have been given in the report.