Policy makers and program managers are faced every day with major decisions resulting from insufficient funding, ongoing complaints about service delivery, unmet needs among different population groups, and limited results on the ground. There is a menu of evaluation types implemented by developing and Organization for Economic Co-operation Development (OECD) countries to tackle a wide range of policy and program management issues, considering time, resources and capacity constraints. International experience highlights the importance of a gradual approach when introducing evaluation tools into country-level monitoring and evaluation (M and E) systems. Different paths may work better for different countries depending on the main purpose of their M and E system, existing institutional capacity, the availability of funds, and external technical assistance.