Think your e-mail messages are crystal clear? Think again. Even if you avoid cryptic instant-message acronyms (and, no, not everyone knows what IMHO and ROTFL mean), some things could still be getting lost in translation.

In a recent study, participants sent and received two groups of e-mail messages — half meant to be sarcastic, the other half intended to be sincere. The recipients misinterpreted the messages’ tone 50 percent of the time. The study, conducted by Nicholas Epley, a behavioral- science professor at the University of Chicago’s Graduate School of Business, and Justin Kruger, an experimental psychologist at New York University, also found that senders were sure their meaning was clear 75 percent of the time, while the recipients had no doubt they had interpreted the e-mails correctly on average 90 percent of the time. In other words, both groups were oblivious to their mistakes.

How does all this affect e-mail exchanges between friends? Say you were 20 minutes late to meet someone and later sent her an e-mail to apologize and make light of your gaffe: “Becky, I’m so sorry I missed you. Let’s try to meet again. I promise I won’t make you wait more than 15 minutes next time!” To you, this message is steeped in self-mockery, but Becky may believe you actually think she has time to wait around for you. And since you’re both sure she interpreted the e-mail correctly, why would you discuss it? To avoid such misfires, consider these tips.

Pause before you hit Send. Think for a minute about the different ways your e-mail could be interpreted, then revise accordingly.

Be wary of emoticons, like smiley and frowny faces. You think they make your intention crystal clear, but the 300-plus available symbols can easily be misread.

When in doubt, pick up the phone. If you’re dealing with a delicate situation, you’re much more likely to get your point across by talking about it.