The multicommodity network flow problem is a classical issue in network optimization, where the objective is to route multiple commodities through interconnected nodes and arcs to minimize the overall flow cost. However, in practical scenarios, parameters such as arc capacities, node demands,...

This paper uses data from the Greater Avenues for Independence (GAIN) initiative to discuss the evaluation of programs that are implemented at multiple sites. Two frequently used methods are to pool the data or to use fixed effects (an extreme version of which estimates separate models for each...