Cost per WAU (weighted activity unit)

Cost per WAU (weighted activity unit) is the cost of one unit of clinical activity. Cost per WAU is calculated at overall trust level and for specific areas of a trust's work, such as by clinical specialty or corporate services function. A trust can see if they are spending more than their peers by comparing costs per WAU.

One WAU equates to around £3,500 'worth' of clinical output. Understand the WAU and how we calculate how many WAUs each clinical activity is 'worth'. Trusts can see if their costs per WAU are higher or lower, compared to this benchmark.

For example, a trust that is paying £4,000 per WAU for coronary angioplasty might be able to find opportunities to improve because its costs are £500 more than average. 

The cost per WAU is also calculated at the overall trust level. By using the same unit for all the different types of activity a trust might carry out, it’s possible to compare trusts with different combinations of healthcare services; some trusts may provide lots of simpler procedures like sigmoidoscopies and other trusts carry out lots of complex procedures like heart surgery. But they can still compare their overall productivity.

You can’t compare figures from different financial years because we have to adjust the WAU values using the annual reference cost data (the information trusts provide about their spending).

Cost per WAU and Adjusted Treatment Cost (ATC)


The cost per WAU and the Adjusted Treatment Cost (ATC) are both measures of productivity. The cost per WAU represents the cost of providing £3,500 worth of healthcare at a given trust, whereas the ATC represents the cost of providing £1 worth of healthcare in that trust.

Trusts with a higher than average total cost per WAU will have an ATC index over £1, and trusts with a lower than average total cost per WAU will have an ATC index less than £1.

Feedback and Knowledge Base