For those of you that haven't heard of it, the stupidity index factor measures a a collective's level of inclination towards stupidity. The basic idea is that when there are more people around, more stupidity arises. I don't remember who's brilliant idea it originally was, but it was probably due to Scottwell and/or Alexandros's consumption of beer.

After some though, prompted by parking lot stupidity, a new formula has been created to approximate the general level of stupidity. A stupidity factor, s, between 0 and 1 is assigned to every person, with 1 being the most serious person and 0 being the stupidest person. The current location is assigned a location multiplier, m, which can range from 0 to 2. A church or temple would have a multiplier closer to 2, while a mall parking lot would have a multiplier of less than .5.

To calculate the stupidity index factor for a group of people in a given location, square the individual stupidity factor for any person that is currently drunk. Then multiply together the stupidity factors for all persons present. Lastly, multiply the product by the location multiplier. The final product is the stupidity index factor. A low number close to zero indicates that something incredibly dumb is about to happen, while higher numbers near 1 (any indices greater than 1 are rounded down to 1) indicate a complete lack of anything entertaining.

For a simple example, take Scott and my presence in his Buick at the Target parking lot earlier this evening. Neither of us were drunk. Assume that both of our individual stupidity factors are .75. The location multiplier for the parking lot is .4.
SIF = m * (sscott * ssharon) = .4 * .75 *.75 = .225
This is a fairly low stupidity index factor, implying that we were very likely to do something inane. In fact, Scott demonstrated what happens when you hit the brake while under the mistaken impression that it is the clutch.