Honoré’s Statistic is a statistical measure of vocabulary complexity, it is a test of Semantic Verbal Fluency and is commonly used for cognitive impairment detection.
The statistic is defined as:
\begin{equation} HS = 100 \log \frac{N}{1-\frac{N_{uni}}{U}} \end{equation}
where, \(N\) is the total number of words, \(U\) the total number of distinct words, \(N_{uni}\) the number of total distinct words used only once.
The idea here is that a higher diversity of vocabulary shows higher Semantic Verbal Fluency.