For eons, the to-do list has been a classic productivity and organisational tool. It’s straightforward, simple and does its job—well, most of the time. Yet, it doesn’t quite optimise work efficiency, especially when you’re in a race against time and your piling in-tray isn’t doing you any favours.

I’ve been a list fiend all my life, and I’ve noticed not all lists are created equal. There’s a general one to make sure you don’t forget crucial dates and tasks. Then, a weekly list that organises your workload for the week, and breaks them down day-by-day. You can also have a separate list that prioritises your tasks for a specific day, which helps inform what takes precedence on that day—your “biggest frog” to tackle, as self-development author Brian Tracy describes it.

No matter how many to-do lists you make though, people tend to leave most of their assignments unfinished and migrate them to the next day (which, based on personal experience, will probably be re-migrated till the end of the work week).

I may have planned and given myself a reasonable amount of time to complete the tasks of each day—usually settling on not more than two to three major assignments per day—but, more often than not, I still end up accomplishing less than 20% of what I’d set out to do. So what’s the problem? Marc Zao-Sanders, the CEO of Filtered.com, might have an answer.

In a study published in 2018, he ranked 100 of the most common tips for productivity, and rated to-do lists as the 7th most effective tool. Holding the first place, on the other hand, is a little thing called time boxing.

It’s basically a fancy word for allocating a period of time (e.g. 2pm to 5pm) to complete a task (e.g. writing an article about time boxing), and it’s a major step up from your average un-time-bound to-do list. Imagine a typical day, where you have to drive your kids to school at 7am, run a few errands at 12pm, attend a meeting at 2pm, and catch a movie at 8pm. The reason why time boxing works to maximise your productivity is because we follow a schedule (whether written or unwritten) every day, and time boxing takes that into account.

We don’t necessarily have the luxury of getting 10 consecutive, uninterrupted hours to ourselves to get stuff done. Even if you simply consider basic needs such as lunch breaks, we’re often left with pockets of time to work. Time boxing allows us to set a time table for ourselves, breaking up a day into separate, more digestible chunks. For instance, you could separate your day into pre-lunch and post-lunch. You can endeavour to complete a major task from 8am to 12pm, and another one from 1pm to 5pm, instead of wasting your morning away on cat videos and relentless emails.

By pairing a deadline with an actual time, we’re able to see the countdown more clearly. Otherwise, we tend to overestimate ourselves and our ability to power through our to-do list with just two hours to spare before the day ends. As long as it feels like we have an abundance of time, we won’t feel the pressure to start working.

Moreover, time boxing forces us to focus on a single task at any time, whereas a to-do list gives you the leeway to switch between assignments (especially when you don’t feel like continuing the task at hand), which is essentially multi-tasking. You, dear reader, may believe you’re a chronic multi-tasker, but it’s really just a myth. Our brains aren’t actually doing two things at once. They’re just undergoing an endless process of stopping and starting, undermining any momentum you’ve built concentrating on a single job.

Far from an OCD practice, this habit helps to bring balance to your life as well. While filling up your hour-by-hour calendar, you could schedule breaks, workouts and even time to “do nothing”, in between more demanding duties—another ace productivity tip. There’s nothing worse than overloading yourself, thinking you can hustle non-stop like a machine, only to crash and burn.

What trips up first-time adopters of time boxing is the difficulty of gauging the amount of time they’ll need for certain projects, those that aren’t as straightforward as doing the laundry. The completion and acceleration of certain projects may be contingent on the productivity of a teammate. Meetings can also drag on and eat into your working hours.

In spite of such uncertainties, time boxing triumphs over to-do lists in how it encourages workers to think objectively about how long a task should take, rather than basing it on circumstance (i.e. how much time is available).

An antidote to Parkinson’s Law, this top hack will enable you to regain control over your time table and productivity, and get rid of the stresses of seemingly insurmountable to-dos.