There are several types of data systems that support data from Part C/619 programs. Although the system types have similarities, each has its own unique characteristics and purposes. The attributes that make one type of data system a particularly good fit for one data-related need or function can be less desirable for another need or function. In fact, a Part C/619 program may have several different types of data systems that meet different needs. This brief describes the characteristics of four common types of data systems: (1) static/reporting; (2) transactional; (3) federated; and (4) centralized. It is important to note that a data system may have attributes of more than one type.