Sentiment Analysis-Probability of sentiment

[charismast0]

Hello everyone, i have studied sas sentiment analysis studio tutorials and i cannot understand the ratio by which the probability of text is being derived.

[CraigDeVault]

The algorithm of probability can be found in the User's Guide for SAS Sentiment Analysis.  Here is what the documentation states for the calculation of the probability:

               for each positive rule match:
                                                            overall_sentiment = overall_sentiment + (weight of the rule * common weighting factor for positive rules)
              for each negative rule match:
                                                            overall_sentiment = overall_sentiment – (weight of the rule)
                                                            overall_sentiment_probability =1/(1+e((0-overall_sentiment)*log(1.5)))