In the pursuit of productivity, some bosses turn out to be their own worst enemies.

Managers are unwittingly wasting their employees' time by making a series of small but costly mistakes, according the Wall Street Journal. Some of the problems come down to simple miscommunications. The findings are part of a study on "organizational friction" by Stanford University professors Robert Sutton and Huggy Rao.

Here are three ways bosses waste their employees' time.

1. Assigning time-consuming tasks.

In one example cited by Sutton and Rao, a boss became fond of announcing new initiatives a few times a year, without knowing how much training and time-consuming paperwork each one entailed. What's more, the new initiatives sometimes led to employees abandoning previous projects altogether. While you should embrace new methods and practices at your company, before beginning a new project, scope out how much time it will require. 

2. Making offhand comments.   

One story the researchers heard involved a CEO noting there were no blueberry muffins at a breakfast meeting. The offhand comment led to employees always buying blueberry muffins for future breakfast meetings without the CEO even realizing he was responsible for the decision. Make sure casual remarks aren't being misinterpreted as direct orders. 

3. Refusing to delegate.

One time-wasting practice known as "cookie licking" refers to managers not letting others take over certain tasks. The researchers cite the example of a CEO who personally interviewed every job candidate at her company (something Jeff Bezos used to do during Amazon's early years). When the CEO insisted on continuing the practice even after her company grew to more than 500 employees, she created such a scheduling backlog that some interview candidates ended up accepting jobs at other companies.

Managers aren't the only ones guilty of wasting others' time, of course. Whatever your rank, make sure you're not making other people's jobs more difficult than they need to be.