It depends on your context really.  In t...

It depends on your context really.  In the UK, the public funding is highly centralised and funds are more or less fixed at the municipal level so PB can't be used to increase or decrease the amount of funding available, with the exception of town and parish councils who can raise their own precepts.

However, PB can and is used to redistribute the funds available to the services that are most needed or wanted by the community.  A way to establish what change has occured to the distribution of funding is to identify what it was spent on prior to PB and track where it was spent throughout a PB process and if and how that changes over time. 

SQW are undertaking a national evaluation of PB for Communities and Local Government and are looking at the issue of redistributive allocation and a costs and benefits model for PB.  They are currently establishing a baseline but in the next couple of years will hopefully be able to provide us with some data on how funds have been redistributed through PB.