Employees with unhealthy habits are causing substantially higher levels of lost workplace productivity, according to new research out of Brigham Young University. Much of that is due to presenteeism — on the job productivity loss attributed to poor health and other personal issues. "Presenteeism is an issue that affects most companies," said Ray M. Merrill, a professor in the College of Life Sciences at BYU. "Studies have shown that when presenteeism is on the shelf, productivity is off."