An aggregate in economics is a summary measure. The aggregation problem is the difficult problem of finding a valid way to treat an empirical or theoretical aggregate as if it reacted like a less-aggregated measure, say, about behavior of an individual agent as described in general microeconomic theory. Examples of aggregates in micro- and macroeconomics relative to less aggregated counterparts are: Franklin Fisher notes that this has not dissuaded macroeconomists from continuing to use such concepts.