Say you have an employee (or a teenager) who is a disaster at time management. Work gets turned in late or not all, everything is always a rush, and real priorities are neglected in favor of short-term pleasures or irrelevancies. How can you help them change their ways? 

Your first instinct might be to threaten and complain, but when it comes to getting other people to change their behavior, nagging doesn't work. If you haven't already observed this truth in your own life, then experts can confirm it. 

"It may be that you have somebody that you're married to or someone in your family that you think needs to get more active or eat better or what have you. What you will probably be incredibly unsuccessful at doing is nagging them until they get it done. It doesn't work," declared psychologist BJ Fogg, director of the Persuasive Technology Lab at Stanford, in an interview a few years back. Shame and motivational speeches also have a low likelihood of success. 

So what does work? When it comes to time management specifically (Fogg has tips for weight loss and exercise), there is no one better to ask than Laura Vanderkam, a time use expert who has published multiple books on how to get the most out of the 168 hours we're all allotted every week. On Medium recently she shared a brilliant mind trick to nudge others to manage their time better. 

To talk about them, first talk about you. 

The problem with nagging or even coaching those who struggle with time management is defensiveness. We all tend to put up walls and plug our ears when we feel we're being criticized. Vanderkam agrees with Fogg that "people do change, but only because they want to change, not because someone else has badgered them enough."

So how do you open a constructive conversation that might actually inspire someone to change their ways? Vanderkam's mind trick is to make the conversation all about you. 

As someone who writes extensively on time use, Vanderkam has tracked her own time for seven years. That level of self-surveillance might be beyond most of us, but Vanderkam urges those trying to help others get a handle on their time to first track their own time use for a week. 

"It would be incredibly invasive for you to ask someone in a dependent position to share their time log with you. But your time log provides a similar opening for a discussion. Share what you can with the other person," she instructs. Obviously, leave out anything sensitive or personal, but try to provide as much detail as you can.  

Talk through any noteworthy moments of the week -- explain why you left early or worked super late one day, or point out when urgent business came up and you juggled your schedule on the fly. Then ask for feedback with questions like: "What surprises you? What do you think is working well? What do you think I can improve on? Is there anything you think I spend too much time on? What areas do I need to give more time to?" 

People may hate unsolicited advice, but almost everyone loves an unvarnished look at the realities and tradeoffs of someone's else's life. Leaders can count on this tendency to get a meaningful conversation about time use going. And once that conversation is going, it's easy to slip in lessons in better prioritization or find your way to a discussion of challenges the other person is facing with prioritization. You might even notice ways to improve your own time use in the process. 

The limits of laying down the law 

This doesn't mean that sometimes bosses don't simply need to lay down the law. Sometimes the right approach is a reminder that 9 a.m. really means 9 a.m. But if the issue is a broader struggle with time management and you value the employee in other respects, Vanderkam insists you'll probably make more progress with this slightly sneaky trick than with harsher methods. 

"If the goal is change, better to use a strategy that might actually lead to that outcome," she concludes (and other psychologists agree). Bosses and parents may want to keep her words in mind the next time they're tempted to nag about missed deadlines or a chaotic calendar.