Paul Taylor, a professor of psychology at Lancaster University, was the lead author on a 2013 study that simulated a workplace with counterproductive employees. He and his fellow researchers offered certain subjects cash in exchange for smuggling corporate secrets to outside parties, and as all of the subjects went about their day as “coworkers,” the researchers monitored their communications.

“If a person is planning to act maliciously to damage their employer or sneak out commercially sensitive material,” Taylor later wrote, “the way they interact with their co-workers changes.” In Taylor’s simulated workplace, employees on the verge of going rogue tended to use singular rather than plural pronouns and words with more negative connotations. When two communicators are in tune, they will typically mimic each others’ words as conversation unfolds—a way of telegraphing cooperation. But “toxic” employees, whether consciously or not, cut down on this mimicry so severely that this metric could be used to differentiate about 93 percent of harmful employees from their well-intentioned peers.

But trying to anticipate misbehavior has its limits. Several employers, from professional dog-walkers to 500-person corporations, for example, evaluate candidates’ credit reports alongside their résumés and cover letters. A bad credit report, the thinking goes, is a sign of financial irresponsibility, which in turn could be read as portending dishonesty on the job. In 2009, about 47 percent of Maryland companies polled by the state’s Society for Human Resource Management said they used credit reports to evaluate candidates for some positions. (13 percent used them for all applicants.) Today, the practice is legal in 40 states.