Indian Health Service (IHS) defines the Active User Population (user pop) as follows:

American Indian and Alaska Native (AI/AN) people who have used services funded by the IHS at least once during the last three year period.

Definition from: Trends in Indian Health 2000-2001

IHS active user population estimates are drawn from data in the IHS Patient Registration System of the IHS National Statistical Database, known as NPIRS (National Patient Information Reporting System).

User pops are residence based, not facility based. That is, a user is assigned to a service unit user population by community of residence, not by the facility where service was obtained. It is possible that a user may live in one service unit and use a facility in another service unit; this user will be counted where he or she lives.

User pops are produced primarily for use as denominators to calculate patient care rates found in the annual IHS publication, Regional Differences in Indian Health. Some of the information you can find in this publication:

• Natality and infant/maternal mortality statistics
• General mortality statistics
• Leading causes of hospitalization and ambulatory visits

User population counts by service unit can increase or decrease. Population changes may result from migration or new facilities that attract new users. Data entry lags or poor quality data entry may also result in a lower user pop.

Each year IHS Division of Program Statistics (DPS) establishes a workload cutoff date for data to be received by NPIRS. For fiscal year 2004 it was December 9, 2004. NPIRS continues to accept workload (registration and clinical) after the cutoff date, but that data is not used for current user population calculations. The good news is that data received after the cutoff date will be used for subsequent user populations since the calculation period looks at the past three fiscal years of data received.

User pop has new uses, please see the new uses page for more information.

For a more technical explanation of user pop processing rules, please see the technical page.

To review Alaska 2004 user pops, please see tables (1) and tables (2).