Opinion polls and perception surveys are designed and conducted to understand the opinions and perceptions of a population about a phenomenon, situation, policy or program. Such polls and surveys can be conducted within the public or private sectors. In the public sector, they can help measure the impact of development or humanitarian policies or programs by governments or donor agencies. Such research is also used to evaluate and communicate the results of reform processes by governments. In the private sector, opinion polls and perception surveys are conducted to help understand customer perceptions about a particular product, i.e., their satisfaction level.