Study finds toxic co-workers surprisingly productive, rule abiding

A Harvard Business School study challenges one of the most common assumptions about toxic employees: that they are lazy or incompetent. In reality, the research shows that some of the most damaging workers inside organizations are also among the most productive.

Researchers Michael Housman and Dylan Minor analyzed detailed assessment, performance, and employment data from more than 50,000 front-line employees across 11 companies. All workers in the dataset were hourly employees in service roles, and the researchers had access to daily productivity metrics as well as hiring and termination records.

Using this data, the authors built a personality profile of extreme toxic workers—employees who were ultimately fired for serious misconduct, including harassment, fraud, theft, workplace violence, or other behavior harmful to an organization’s people or property.

One of the most surprising findings is that toxic workers are often hard workers. On average, they outperform their peers in terms of output, which helps explain why organizations tolerate them longer than they should. As the authors note, there is often a perceived trade-off: unethical employees may generate strong short-term results, tempting managers to overlook their behavior.

The study also identifies several traits that reliably predict toxic behavior. First, toxic workers tend to be highly self-regarding—in other words, selfish. They fail to internalize the costs their actions impose on coworkers, which increases the likelihood of harmful behavior.

Second, toxic employees are often overconfident. This inflated sense of ability can lead to excessive risk-taking, as individuals overestimate their chances of success or believe they are unlikely to face consequences for misconduct.

Most counterintuitively, toxic workers frequently describe themselves as strict rule followers. Employees who claimed that rules should always be followed—without exception—were statistically more likely to be fired for breaking those same rules. The researchers suggest this may reflect impression management or Machiavellian tendencies rather than genuine ethical commitment.

From a financial perspective, the implications are stark. Avoiding the hire of a toxic employee saves an estimated $12,489 due to reduced turnover, as coworkers are far more likely to quit when exposed to toxic behavior. By contrast, hiring a superstar employee in the top 1% of productivity generates only about $5,303 in added value.

The conclusion is clear: bad workers can have a stronger impact on organizations than good ones. Housman and Minor argue that firms should adopt more multidimensional hiring and evaluation practices—screening not just for productivity, but also for integrity, judgment, and corporate citizenship.

In short, avoiding toxic workers is not just a cultural or ethical imperative—it is one of the most financially effective decisions an organization can make.