Comparing different versions of expenditure is a common and extremely
important functionality. In the case of budgeted (planned) and actuals
(or different versions of a planned budget) it is comparing the same
budget line between planned and actual. We also want to compare between
countries: for example spending on defence in one country vs another (or
spending on the same cofog codes). This is a really important feature
and one that OpenSpending will support.
Exactly how OpenSpending will do that needs discussion. Has anyone had experience with generating spending data comparisons? What is important to think about, especially, say, when generating visualizations of such comparisons. Is there a need to make sure that two datasets that classify spending by COFOG have some agreed way to actually know they are referring to the same classification scheme? For those that don’t share a classification scheme, is it worth supporting comparing those datasets? How? What else is there to think about?