Typealyzer.com did put uclassify's personality dichotomy scripts together for each of the four letters for MBTI a couple years ago.

What is your algorithm based on?
As a side note, I copypasted one of my essays into uclassify's age recognition thing. It said I was probably old (like over 40). Then again, bear in mind that how I write my essays differs from how I write in an informal setting.