Seonglae ChoPointwise mutual information (PMI)
Negative PMI values are harder to interpret and evaluate; relatedness is easier to evaluate as opposed to un-relatedness
Positive Pointwise mutual information (PPMI)
Pointwise mutual information
In statistics, probability theory and information theory, pointwise mutual information (PMI),[1] or point mutual information, is a measure of association. It compares the probability of two events occurring together to what this probability would be if the events were independent.[2]
https://en.wikipedia.org/wiki/Pointwise_mutual_information