The Average Propagation Length: Conflicting Macro, Intra-industry, and Interindustry Conclusions

The average propagation length (APL) has been proposed as a measure of the fragmentation and sophistication of an economy. For a one-sector economy, we show that the APL is strictly proportional to the macro multiplier of that economy. The same holds for strong intra-industry linkages. Hence, for comparing economies and comparing single industries, the concept of the APL is of no value. For pure interindustry linkages, however, we find that the length of the supply chain between two different industries is negatively related to the strength of the multiplier between those two industries, be it weakly. Hence, the APL should only be used to compare pure interindustry linkages.