Data sets are lists of variables collected to meet the minimal requirements of the group's goals, often with an additional list of elements that are recommended for the most effective operation. Required data sets are not the same for all standard setters. For example, the underlying interest of the CoC is the quality of case management and medical care provided by the medical facility. Detailed information is collected on patients' prognostic factors, treatments and services provided, and short- and long-term outcomes. The NPCR data set was specified to meet cancer control goals of assessing timely diagnosis and reporting of cases, demographic factors affecting surveillance, first course of treatment, and mortality. SEER's data incorporate the goal of epidemiological research analysis and include items to indicate data quality. Many of the data needs for these and other programs are similar, and the required data sets naturally overlap.
Most hospital-based (institution-based) registries are required to meet the standards of more than one organization and may also add specific variables to meet internal needs. Most registries in hospitals or other medical facilities are required to meet the data standards of both the CoC and a state central registry. The CoC data set, in turn, includes items necessary to code TNM categories and other items required by its member organizations. Most state registries, in turn, must meet data requirements set by SEER, NPCR, and state legislative mandate, in addition to those they set internally. Most states require at least some data elements beyond the set required by CoC, and most states do not use all CoC-required elements.