On the self-reported IQ question, please specify that the test is supposed to have a mean of 100 and stdev 15, and scores from tests with different scales should be rescaled.

It might be useful to have two different questions:

1. If you've taken an IQ test administered by a psychologist, and still have the scores, please tell us your score here. If your test was not normed to a mean of 100 and standard deviation of 15, please renorm it before reporting it.

2. What do you estimate your IQ to be? As with the previous question, please use a mean of 100 and standard deviation of 15.

[edit]We might want to give people an opportunity to say what age they were when they took their IQ test, or ask what test it was- that way we can separate out childhood IQ and adulthood IQ, which can diminish many of the criticisms of childhood IQ tests.