Improvement on the association strength: Implementing a probabilistic measure based on combinations without repetition

Abstract The use of co-occurrence data is common in various domains. Co-occurrence often needs to be normalized correct for the size effect. To this end, van Eck and Waltman (2009) recommend a probabilistic measure known as association strength. However, formula, based on combinations with repetition, implicitly assumes that observations from same entity can co-occur even though intended usage these self-co-occurrences are nonexistent. A more accurate without repetition introduced here compared original formula mathematical derivations, simulations, patent data, which shows overestimates relation between pair some pairs overestimated than others. new available EconGeo package R maintained by Balland (2016).