A National Weighted Activity Unit (NWAU) is a measure of health service activity expressed as a common unit, against which the National Efficient Price (NEP) is paid. It provides a way of comparing and valuing each public hospital service, whether they are emergency department presentations, admissions or outpatient episodes, weighted for clinical complexity.

The average hospital service is worth one NWAU – the most intensive and expensive activities are worth multiple NWAU, the simplest and least expensive are worth fractions of an NWAU.

The NWAU is updated annually, and is named to reflect the year of its operation. This means that in 2012-13, the NWAU against which the NEP is paid is called NWAU(12). In 2013-14, the NWAU is called NWAU(13), and so on.

Independent Hospital Pricing Authority's National Pricing Model Technical Specifications each financial year explains how the IHPA developed the activity-based funding models for the service streams to be funded. It also shows how the NWAU were developed, and provides guidance to hospitals, Local Health Networks and State and Territory health authorities on how to apply these to hospital activity.