You're right. We've found that there's not enough data to support informed decisions. There is some data, but it isn't being gathered in a consistent fashion across government. From what we could tell, each department is responsible for figuring out how to monitor its employees' in-office attendance.
We identified the methods used and recommended that the government implement a standardized method to ensure that the whole public service is gathering this data the same way. Once that's done, we'll know how public servants are using office space and decisions can be made about which properties to dispose of.
To sum up, we lack that basic data. There has been progress, but I think a single whole-of-government approach is needed.