  Countries and cities are likely to enter economic activities that are related
to those that are already present in them. Yet, while these path dependencies
are universally acknowledged, we lack an understanding of the diversification
strategies that can optimally balance the development of related and unrelated
activities. Here, we develop algorithms to identify the activities that are
optimal to target at each time step. We find that the strategies that minimize
the total time needed to diversify an economy target highly connected
activities during a narrow and specific time window. We compare the strategies
suggested by our model with the strategies followed by countries in the
diversification of their exports and research activities, finding that
countries follow strategies that are close to the ones suggested by the model.
These findings add to our understanding of economic diversification and also to
our general understanding of diffusion in networks.
