As any serious job-hunter knows, it helps to dress smartly and smile at that all-important interview. But research has revealed that a firm handshake is what really matters when it comes to impressing potential employers. Although previous studies have shown a limp, "wet fish" handshake indicates shyness, and a firm "pump" confidence, there has been little evidence about the effect this has on an interviewer. The US research looked at 98 undergraduates taking part in mock interviews with businesses. As each was graded on their overall performance, five "handshake raters" also marked them on their grip, strength, duration, vigour and eye contact. Professor Greg Stewart, from the University of Iowa, who led the study, said those who scored highly with the handshake raters were also considered to be the most hireable by the interviewers. Students with "wimpy" shakes were judged to be more timid and less impressive. The study, published in the Journal of Applied Psychology, also found women with a firm handshake were likely to be evaluated more favourably than their male counterparts.