The document discusses interoperability and data linkage in health information systems. It defines key terms like interoperability, fragmentation, integration, and data warehousing. It describes how linking data sources like RHIS, EMRs, and surveys can improve health systems by enabling analysis of relationships between different types of data and more timely monitoring. Specific examples are provided of countries that linked their LMIS, HMIS, and HRIS systems to generate new indicators and identify supply issues. Decision support systems and enterprise architecture are introduced as ways to facilitate data analysis and alignment of health IT investments.