Both the Project Company and the Authority should independently collect comparative information when undertaking a benchmarking exercise. The Project Company will require this information for identifying a benchmark cost of the services, and the Authority will need it to examine, interrogate and validate the result of that exercise. Authorities must ensure that data used is a valid comparator, transparently compiled. Making accurate comparisons is difficult, and often the data is likely to need to be adjusted to take into account project specific aspects of the service provision, and factors such as regional variations. The Project Company's own costs of providing the services are not a valid comparator.