The relevance of context in disambiguating natural language input has been widely acknowledged in the literature. However, most attempts at formalising the intuitive notion of context tend to treat the word and its context symmetrically. We demonstrate here that traditional measures such as mutual information score are likely to overlook a significant fraction of all co-occurrence phenomena in natural language. We also propose metrics for measuring directed lexical influence and compare performances. Keywords: contextual post-processing, defining context, lexical influence, directionality of context
