I don't know if Ekman is real or not (probably not), but any serious study of predictions should report both precision (are your accused liars all guilty?) and

I don't know if Ekman is real or not (probably not), but any serious study of predictions should report both precision (are your accused liars all guilty?) and recall (did you catch all the liars?), not make statements like "70-percent accuracy." Especially if we are using these techniques for security screening, these numbers are essential. We'll also need to educate security personnel about the unintuitive nature of false positives, where even if a test achieves a low false positive rate, a given flagged person still has a low chance of being a liar (see http://en.wikipedia.org/wiki/False_positive_paradox http://en.wikipedia.org/wiki/False_positive_paradox).