  In the information science literature, recent studies have used patent
databases and patent classification information to construct network maps of
patent technology classes. In such a patent technology map, almost all pairs of
technology classes are connected, whereas most of the connections between them
are extremely weak. This observation suggests the possibility of filtering the
patent network map by removing weak links. However, removing links may reduce
the explanatory power of the network on inventor or organization
diversification. The network links may explain the patent portfolio
diversification paths of inventors and inventing organizations. We measure the
diversification explanatory power of the patent network map, and present a
method to objectively choose an optimal trade-off between explanatory power and
removing weak links. We show that this method can remove a degree of
arbitrariness compared with previous filtering methods based on arbitrary
thresholds, and also identify previous filtering methods that created filters
outside the optimal trade-off. The filtered map aims to aid in network
visualization analyses of the technological diversification of inventors,
organizations and other innovation agents, and potential foresight analysis.
Such applications to a prolific inventor (Leonard Forbes) and company (Google)
are demonstrated.
