Martin Gardner claimed to have inside information that files in Rhine's laboratory contain material suggesting fraud on the part of Hubert Pearce. Pearce was never able to obtain above-chance results when persons other than the experimenter were present during an experiment, making it more likely that he was cheating in some way. Rhine's other subjects were only able to obtain non-chance levels when they were able to shuffle the cards, which has suggested they used tricks to arrange the order of the Zener cards before the experiments started.