It’s the 21st century! Woohoo! Being the future, we’ve augmented our brains with amazing technology that lets us multitask and be super productive on a dozen things at once! Haha, just kidding. Actually, if you multitask, it will turn your brain to mush and make you unable to perform even simple mental tasks. But since the first thing to go is your ability to assess your productivity, you’ll feel great while your abilities descend to the level of a flatworm.

That doesn’t change the fact that we have multiple projects going on or several goals to hit at once. So, with only one attention span, we need to decide what to work on next. Usually, that means focusing on what seems the most urgent at the time. And usually we define “urgent” as “needs to be finished most quickly.”

But if that’s your definition of urgent, it won’t quite work. It doesn’t take into account projects that need more time to finish. As a result, choosing the task with the earliest deadline to cover first may be keeping you from hitting other deadlines on time. There’s a better way.

Instead of using the soonest deadline to prioritize, focus on what needs to be started the soonest.

Establish the Lead Time of Your Tasks

In order to know what needs to be started first, you need to figure out lead times. A lead time is how far ahead of a deadline you need to complete the task. You’re sneaking out of work for a coffee break. Your artisan cafe of choice only takes cash, so you need to go to the ATM. The five minutes it takes to grab cash from the ATM is your lead time. That’s five minutes not spent getting your caffeine fix.

To establish your lead times, add up all the preparation time you’ll need for that task. Then you’ll know exactly how far in advance you have to start.

Intern MG invited me to his potluck. He asked me to cook green beans and mashed potatoes. He’s either very brave or very foolish. I said yes! I am very sadistic.

MG is a real stickler for deadlines: If I’m even five minutes late, he just might ask me to leave (while keeping my green beans, of course). Even Martha Stewart cowers in abject inadequacy when confronted with intern MG’s standards.

The green beans take five minutes of prep and 15 minutes to make. That means my green bean lead time is 20 minutes. The mashed potatoes take 20 minutes to cook and five minutes to mash. That means my potato lead time is 25 minutes.

Now that I know my lead times, I need to figure out how to do all of that on time.

Do the Projects with Longer Lead Times First

Remember that urgency is about what needs to be started first. Once you know everything’s lead times, what’s most urgent is what will take the longest, so everything gets finished.

Take the lead time of the long task, and subtract the lead time of the short task. That tells you how much earlier you need to start the long task. Green beans take 20 minutes total, while mashed potatoes take 25. The longer task is potatoes at 25 minutes. Subtract the 20-minute green beans and you get five minutes. You must start the potatoes five minutes before starting the green beans.

In this example, the beans can be prepared while the potatoes are potato-ing. If your two tasks can’t be overlapped like that, you’ll have to do them one after the other. In that case, just add their lead times together to find out when you have to start the whole project.

If I decide to bring peeled carrots and sliced turnips to MG’s potluck, there’s no way to overlap the tasks, since all the time for each dish is used preparing the food, rather than waiting for it to cook. If the lead time for the carrots is 45 minutes (because I lost my carrot peeler and have to use my fingernails), and the lead time for the turnips is seven minutes (because, hey, turnips), I have to spend a total of 52 minutes preparing. Of course, I speed date those two tasks until they’re complete! (For more, see the past Get-It-Done Guy episode on speed dating tasks.)

Once you’ve found out what to start with, you need to know when to get started.

Find Out the Start Time in Relation to the Deadline

Now you know which task starts in relation to the others. But when do you start each one?

Calculate the start time of each task by subtracting the lead time from the due date. You’ll end up with a collection of times when you could start each task that would allow you to do it by the deadline.

The party started at 5:30 PM, and it takes 30 minutes to get to MG’s minimalist, rent-controlled studio apartment. So I subtracted the half-hour lead time from my arrival deadline. Now, I knew I needed to leave at 5 PM to get there on time.

I’m starting the mashed potatoes first, and then the green beans, and my deadline is 5 PM. As we saw before, we need to start the potatoes five minutes before the green beans. The two together take 25 minutes. So my start time is 4:35 PM. Now I can impress intern MG with my punctuality, and bring the food I need to!

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This article was originally published on Quick and Dirty Tips. It has been republished here with permission.