Google might sometimes help uncover some blatant deceptions, and routine background checks can help you find more. A recent experimental study by Harvard University’s Deepak Malhotra, Lyn M. Van Swol, and Michael T. Braun suggests that other techniques, like watching language, might also work: liars tend to use more expletives, third-person pronouns, and complex sentences than truth-tellers, in addition to being more generally verbose. But you need training to pick up on these things. In my experience, the only way to get close to the whole, unvarnished truth is to have probing conversations with a variety of people who have worked closely with the candidates you’re considering.