Just calculate the "distance" of each set of answers from the average, throw away those that are beyond some limit, recalculate the average.
Play a little with that algorithm and the "some limit" will probably be obvious. On 6/1/05, Thane Sherrington <[EMAIL PROTECTED]> wrote: > Here's a a problem I'm wrestling with. I have a company doing on-line > performance reviews. Each employee rates a set of other employees on a > survey which has six categories with between 3 and 7 questions in each > category. > > The problem is that there are a couple bad apples who blow through the > surveys rating someone either all 1s or all 5s, throwing off that person's > ratings and effectively ruining the value of the performance review. > > My first attempt to stop this was to time the surveys. People who finished > them in less than five minutes (the cheaters generally take two minutes) > got a message telling them to go back and think about their answers and try > again. That didn't work because it turned out that several non-cheaters > print out the review and do it on paper, and then login to enter the > answers - since they were working from paper, they finished the review in > under five minutes. > > Then I tried checking each category - if all the answers in a specific > category were the same, I rejected the review and told them to do it > again. No soap - occasionally there are legitimate reviews where one > category has all the same answers. > > So then I switched to checking the entire survey. If all the answers are > same, the survey gets rejected. It took the cheaters slightly under a > quarter of a second to figure that one out, as you can imagine. > > The surveys are all anonymous, so I can't simply go to the person entering > the survey and tell him/her to stop cheating. > > Can anyone think of a way to monitor and block the cheaters? > > T > > -- G. Waleed Kavalec ------------------------------- Copyright: G. Waleed Kavalec 2005 This message may be resent and/or republished provided the content and this notice are kept intact.
