Over at Wandering Scientist about two years ago, the blogger known as Cloud posted a graph highlighting a fascinating little observation about productivity. Charting her hours at her desk/office against actual hours worked, and also against actual work produced, she found that her optimal work week was around 45 hours. At 45 hours in her office, she produced pretty close to 45 hours worth of work. At 50 hours, however, she was only working — defined as being anything close to on-task — for 47 of those, and producing the equivalent of 45 hours of work. At 55 hours, she was still working for only 47 hours, and she was down to about 41 hours of usable stuff as she made mistakes and had to discard things.
In other words, those last 10 hours worked were not only wasted, which would stink in terms of personal opportunity cost. They actually destroyed value for her organization. Working past her work limit was a big mistake.
I thought it was an interesting idea at the time, so I was happy to see Cloud elaborate more on her work limit concept in an ebook that’s out today (under the less bloggy name M.R. Nelson) called Taming the Work Week. In it, Nelson describes her strategies, as a project manager in biotech, for keeping both her work week and her team members’ work weeks, under control. That’s not just because she wants to be a good boss — though I’m sure she does — it’s just that she’d rather get 45 hours of work per week out of her team than 41 hours. And if keeping them at the office 55 hours means she gets 41 hours, and keeping them there 45 hours means she gets 45 hours, well, it’s clear which one is better.
She advocates keeping track of your time, and figuring out ways to keep making progress even if you don’t feel motivated on a project. It goes without saying that if you want to produce 40-45 hours of work in 45 hours, you need to spend the lion’s share of your time on task, rather than surfing the web and feeling sorry for yourself. That doesn’t mean you can’t take breaks — breaks are productive and count as work! — but take conscious breaks, rather than losing an hour to reading something you didn’t mean to read. Nelson, for instance, enjoys tea time many afternoons.
She also, interestingly, doesn’t leave a bit early if she’s finished her major tasks for the day. She could walk out, but part of getting a lot done in 40-45 hours per week is to consistently work 40-45 hours per week, even if a week’s load is on the light side. Instead, she picks a 15-minute task or two from her list of future tasks, and knocks some of them off. “Getting these little tasks done before they become urgent means that I can usually find some longer increments of time during the day in which to tackle my larger tasks,” she writes. “I’ve learned that if I let the little things slide, they inevitably pop up as emergencies when I can least afford the time to handle them.”
I’ve tracked my time for many weeks over the past few years, and have found that 45 hours per week is pretty much my happy space, too. I have worked more — the week I logged for the “Mind Your Hours” week of the #SuccessAtWork challenge was 56 hours — but I often have trouble focusing the next week after a week like that. I have worked less, too. I have three little kids, and they get sick, or I take on personal projects like running a marathon. I don’t miss deadlines on things I’ve committed to. But I do find myself under-investing in the soft side of work: sending emails to reconnect with people, taking a phone call that might lead to something later on. For me, 45 hours per week is a pretty good balance. If I sleep 8 hours per night (56 per week), that leaves 67 hours for other things: runs, reading One Morning in Maine several times, reading Night of the Moonjellies several other times, dandelions, hugs, etc.
What’s your work limit?
In other news:
The paperback of All the Money in the World will be out a week from today! This updated version of the book also contains, as bonus material, the first ever print version of What the Most Successful People Do Before Breakfast. Thanks for checking it out!
If you are looking for the 168 hours time log, it’s here.
Photo courtesy flickr user thecrazyfilmgirl
What an interesting post! Her time study should be required reading for all employers 🙂 I am sure it would be an interesting experiment for each of us to run and find out our optimal work hours per week.
@Stacey- exactly. At a certain point it’s hard to focus. Of course, there’s an opposite problem, which is that sometimes we stop before the point of diminishing returns. The key is finding the right balance.
Coincidentally, I’ve been reading One Morning in Maine multiple times/day too.
@TG – at least it’s a good story! One of my favorites from childhood. I just like the image of digging for clams in the mud.
I look forward to reading the book!
This and other productivity should be required reading for managers who tend to promote those who stay at the office longer. I think my work limit is 40 to 45 hours, 50 hours only for special projects.
@oilandgarlic – I wish there were a school for managers where things like this were documented for people. Alas, most people kind of figure it out as they go along, sometimes erroneously…
Most research I’ve seen still quotes that super old factory study that finds 40 weeks is optimal. You’d think there would be more recent prominent work looking at different types of jobs and so on. I mean, there’s a ginormous productivity literature, but I don’t think it looks at the basic how many hours question across different contexts… just lots of quoting that factory study and saying it may not apply.
That was my experience, too- I couldn’t find more recent studies. There are, however, some less rigorous things that suggest knowledge workers have even fewer hours for optimum productivity. Most estimates I’ve seen are 6 hours/day, but again those aren’t from rigorous studies. It makes sense- people don’t think about it, but the brain is actually our most energy hungry organ. It isn’t really surprising that it can get fatigued just like muscles do. My opinions on work hours are based on the old studies, the estimates I’ve seen for knowledge workers, and then my own observations on how my teams and other teams at my companies have behaved. And also my own experience, which I’ve replicated many times in various time tracking exercises.
Thanks for the nice post, Laura, and the kind words about the book, everyone!
Congrats on the ebook Cloud!!!
Interesting, Cloud. I’d say 6 hrs sounds about right for me for real work; I can put in more hrs with meetings and such but not brain function. Congrats on the book…I kindled it.
Great post. You mentioned how you had some difficulty focusing after that 56 hour work week. I feel that way too if I start going past 50 hours. I also have kids and find this to be a lot of work, not just parenting but managing their child care, summer camp plans, trips for them to see grandma, managing playdates, etc. So it’s like this is a second job that takes energy, too. When I’m feeling burnt out, I begin to envy those who don’t have all these extra responsibilities outside of work. They can just come home and rest! Anyway thanks again for this post – I saw your guest post on the iDoneThis blog which is what led me to your blog today.
@Gale – welcome! Thanks for checking out the blog, and I hope you’ll stick around. Yes, the mental load of home work can make it hard to relax. That’s one of the key aspects of time management that many of us need to work on — truly creating down time and compartmentalizing the endless to-do list.
Much of the work cited by the Robinsons is focused on manufacturing work, Sara Robinson writes that knowledge workers actually max out at about six hours per day, not eight. I haven’t been able to find her source, and as of this writing she has not returned my e-mail asking what the source is. It could be a survey conducted by Microsoft in 2005 intended to promote the value of the company’s productivity software. Out of a 45 hour work week, survey respondents consider about 17 hours to be unproductive. That’s 28 productive hours per week, or just 5.6 hours per day given a five day work week. This is self-reported productivity, and much of that lost productivity is actually due to meetings, but this is not out of line with the industrial research cited by the Robinsons.