Job interviews are still the most common, and the most heavily weighted, pre-employment assessment tool. Most people think that they are pretty good judges of candidates' intelligence, motivation, interpersonal skills and leadership potential. However, research has shown that unstructured job interviews have a validity of roughly 20%, meaning that flipping a coin would actually be more likely to predict who will succeed in the workplace. Training interviewers and structuring interviews can boost validity to roughly 50%. Given that a back-of-the-envelope calculation is that each poor hire costs organizations one year's total compensation (to recruit, process and train a replacement), it is somewhat mysterious that more organizations do not train interviewers, structure interviews, or hold hiring managers accountable for their hiring decisions. Malcolm Gladwell wrote a great article about the basic psychology of interviews in The New Yorker a few years ago.