If only there was a way for you as an employee to ensure your personal growth and improve your performance long after the initial training. It would almost guarantee continual promotions and upward mobility in your career. Or, if you’re an employer or a manager, imagine having an easy-to-implement method to ensure that your workers were improving their skills on a daily basis, maximizing your productivity.

According to a recent study published by Harvard Business School, there is in fact a method that accomplishes these objectives.

Some participants in the study spent fifteen minutes at the end of a workday writing and reflecting on their experiences. They weren’t given any prompts other than to record what was on their minds, so they didn’t have to use a positive or negative slant. The participants who did the reflection in writing scored 22.8 percent higher on an assessment than those who didn’t.

Could spending fifteen minutes a day reflecting about work realistically make an employee more productive?

This theory goes against some conventional training methods because it takes away from actual practice on the job. But it provides strong evidence that practice alone does not make perfect. The study’s authors explain on page 8:

Imagine you are an avid tennis player who has twenty minutes left at the end of your weekly class. You would like to improve your serve, and you see two ways of doing so. You could either hit as many serves as possible in the next 20 minutes, or you could hit just a few serves, and then pause to analyze your stroke. Every minute you spend reflecting on how to get better is costly in terms of lost practice time. Conversely, every minute you spend hitting serves consumes time you could have spent reflecting on how to get better. What would be the optimal choice for you to maximize learning? In other words, which learning activity provides the highest benefits in terms of future performance: learning by doing alone, or learning by doing coupled with learning by thinking?

Writing in particular is an effective way to reflect because it helps you stay focused when compared to internal reflection. It forces you to process what happened during the day and to find patterns. Writing something down can also help you see what you can change and how you might be able to improve.

In an era when many companies are striving to work smarter instead of working harder, this finding can have significant implications. Of course, in many industries setting aside fifteen minutes a day for every employee to do some reflective writing just isn’t feasible. But it may be a practice worth implementing during trainings. And no matter where you’re at personally in your career, it’s a discipline worth pursuing if you want to advance.