You want your employees to be happy. You want your employees to enjoy a reasonable work-life balance. You know the best way to improve employee performance is to give people the time and space to recharge and refresh.

So you do what seems logical and create a policy. You tell people not to check -- much less respond -- to emails sent after normal work hours.

"There," you think. "That should solve the problem."

Nope. According to research published earlier this year in Journal of Management, formal policies don't limit the stress, anxiety, and impact on personal time caused by after-hours emails

What matters more? As the researchers put it, "People who influence my behavior at work think that I should monitor electronic communication away from work."

If a supervisor ever just implies I should check my email, I'll check email. If a colleague ever just implies I should check email, I'll check my email.

Policies are just words; reality is what matters.

And then what happens? Policies aside, people who feel they have to check their email when they're not at work report higher levels of stress, higher levels of anxiety (because who knows what the next email may bring), a negative impact on personal relationships, and even negative health effects.

All of which makes sense. Every time I go there (to my email), I'm no longer here. I'm back at work. And my personal life suffers.

Granted, establishing formal job responsibilities can help. "Setting expectations upfront," the researchers write, "may not only reduce anxiety and negative affectivity in focal employees, but also increase understanding from significant others by re-framing boundaries and surrounding expectations around employee work-time." 

Or in non-researcher-speak, if I and my significant other know going into it that checking email during certain parts of the day or evening is part of my job, neither of us will be quite as bothered.

But still. "Certain parts" never stay certain. Expectations almost always tend to expand. 

Research backs that up, too. A study published in Organizational Behavior and Human Decision Processes shows that co-workers significantly overestimate how quickly senders expect replies to non-urgent emails.

Especially those sent outside "normative" hours like nights or weekends.

The researchers call it "email urgency bias," a phenomenon caused at least in part by the fact that response speed has increasingly become a proxy for dedication and hard work. (The same way many managers see working long hours -- call it the "butts in seats" bias -- as a proxy for productivity.)

Add it all up, and policies and guidelines don't matter.

What matters is what you expect.

And what you do.

If you want to help your employees avoid the negative impacts of off-hours emails, don't send them. Tell the people who work for you not to send them.

Sure, you might include a line like, "Please don't feel the need to respond today. We can talk about it on Monday." But even if they know they won't have to respond, that doesn't mean people won't check to see whether you sent any emails.

The only way to reduce the anxiety I might feel from wondering whether you sent me an off-hours email is to never send off-hours emails. Then I won't wonder.

Then I can disconnect, both actually and mentally. 

I'll be a lot less likely to burn out since I won't feel I need to be available at all times.