This document discusses the importance of health information systems (HIS) and how to assess them. It defines HIS as information processing and storage systems that can be within a single institution or across multiple healthcare organizations. HIS are important because they produce data needed by various stakeholders to better manage health services and monitor progress towards health goals. The key components of an HIS include inputs, processes, outputs, and dissemination/use of information. Basic steps for assessing an HIS involve forming terms of reference, collecting and reviewing data, identifying indicators, designing assessment tools, analyzing results, and making recommendations. The document also provides an example assessment of Cameroon's HIS using the WHO Health Metrics Network framework.