I came across the concept of lexical density while reading "Embracing a New Creed: Lexical Patterning and the Encoding of Ideology" by Oliver Mason and Rhiannon Platt and was wondering what practical benefit it is for linguistic analysis.
 Oliver Mason and Rhiannon Platt (2006) "Embracing a New Creed: Lexical Patterning and the Encoding of Ideology", College Literature, vol.33, no.2, 155—170.
I've revised my understanding of lexical density based on re-reading the article in question and getting a clearer understanding of the actual calculation. I now understand lexical density to be the proportion of content words (nouns, main verbs, adjectives, and adverbs) to function words (articles, prepositions, conjunctions, auxiliary verbs, and pronouns). Essentially I guess I understand it as the proportion of words that give meaning to the constituent clauses and phrases over against the words that appear in nearly every context and lend little to no meaning.