Data Access & Quality

SEER Data

The SEER Program currently collects and publishes cancer incidence and survival from population-based cancer registries covering 18 geographical areas in the United States, providing data for one quarter of the population. Data on more than six million in situ and invasive cancer cases are included in the database with more than 350,000 cases being added each year from the SEER coverage areas. The SEER Program is the only source of population-based historical as well as current information on patient survival and stage of disease. The mortality data reported by SEER are provided by the National Center for Health Statistics. The population data used in calculating cancer rates is obtained periodically from the Census Bureau.

Updated annually and provided as a public service in print and electronic formats, SEER data are used by thousands of researchers, clinicians, public health officials, legislators, policymakers, community groups, and the public. The SEER Program provides data free of charge through reports on cancer statistics and in a limited-use data file, which currently can be obtained on a CD-ROM or access may be provided through a server at NCI. Software is also provided free of charge by NCI that aids in the analysis of the SEER database (SEER*Stat) and can be used to analyze data from other cancer registries (SEER*Prep and SEER*Stat).

Quality Control Activities

The SEER Program is considered the standard for data quality around the world. Quality control has been an integral part of SEER Program activities since its inception in 1973. Currently, quality control studies of various types, including casefinding, recoding, and reliability, are conducted in even number calendar years. The first two study types are carried out by a group of auditors which includes a qualified staff member from each SEER registry. The auditors travel to registries other than their own in order to collect data. These studies are designed using appropriate statistical procedures that provide for obtaining measures that can be used to assess the performance of a registry. Registries that do well are recognized, and individuals that do well in the reliability studies are recognized as well. In odd numbered calendar years, training programs are conducted at selected SEER registries and in conjunction with the annual meeting of the National Cancer Registrars Association that focus on problem areas identified from the quality control studies as well as any changes being introduced in data collection procedures. Another quality control tool is the Data Quality Profile which is created for each registry. This profile provides an assessment of the extent to which each registry provides data that meet certain standards that pertain to the percent of cases for which a data item is unknown, reporting delay, and the quality of data on vital status. The SEER Program has also developed an extensive set of inter- and intra- field edits that are used to identify and correct errors in the data.