Because testing for psi abilities often includes multiple series of tests, experimentors look for responses that are significantly above chance. For example, if you had 100 runs of a guessing test, guessing 51 or 52 correctly is above chance, but not significantly enough above chance to be considered remarkable. Generally, a set of responses must be 5% above chance (less than 1 in 20) to be considered significant. In the example of 100 runs, a success rate of at least 55 would be required to be considered significant.