Researchers have estimated that chronically late employees cost the economy billions of dollars. If that's not reason enough to encourage your workers to get to their meetings on time, extreme agitation triggered by other people's tardiness probably is.

While it's hard not to get offended by someone's disregard for a set schedule, psychologists say there's hardly any reason to take it personally. Mostly people are late simply because humans are terrible at predicting how long tasks will take them. 

On average, people underestimate project completion times by as much as 40 percent, Roger Buehler, a psychology professor at Wilfrid Laurier University, told the Wall Street Journal. Unfortunately, since this flaw is practically ingrained in our DNA, tardiness is one of the most difficult habits to break.  

But experts have come up with several techniques for improving the ability to better estimate a task's length of time. If you or someone you know could benefit from some practice, check out the tips from WSJ's Sumathi Reddy: 

Recall a past experience.

If you're working on as task that you've done before -- like your taxes, for example -- think back to how much time it really took you last year. You'll likely require no less time to get it done now. 

Get detailed. 

When Justin Kruger, a professor at NYU's Stern School of Business, asked people to estimate how long it would take them to get ready for a date, do all of their holiday shopping, format a computer document and prepare a meal, participants came up with much more accurate guesses when they "unpacked" a task. This means they considered the very detailed step-by-step process required to get their to-do items done. 

Pretend you have an outsider's view. 

In a 2012 study, Buehler found that when he prompted people to mentally picture their schedules from an outsider's perspective, they were less likely to be unrealistically optimistic about how much time projects would take to complete.