In some organizations, management has developed a goal of maximizing efficiency and keeping utilization high. The logic goes, if people are slacking off, then they have time when they could be producing value for the company but are instead just wasting money. And if people are 100% utilized, then they’ll be providing the most value possible.
This isn’t true. 100% utilization actually has a number of negative impacts, so it is important to have some slack time. It is equally important to make sure that time is used properly, though.
In regards to project management, I first encountered the word “slack” in the context of critical path management (CPM). Using CPM, you first break down all of the necessary requirements for a project into distinct tasks, determine which tasks depend on other tasks (thus creating a chain of tasks, from one dependency to the next), estimate how long each task will take, and then calculate backward and forward along the chain. The goal is to find out how many total days will be needed, and which tasks will or will not have slack. For those that do not have any extra time available, we label them as “critical,” and any delay in starting or completing those tasks will delay the overall project. For tasks that are not critical, we’ll have an idea of how many days we can delay before there is an impact on the project schedule.
You never want to schedule your project so tightly that you have no slack time. There will always be unknown unknowns that crop up and demand extra time and attention, and without slack, those would result in a late project. You may also learn things along the way that provide new opportunities to make the project better, but they might take additional time. Having some room to work creatively and try new things is always to the good. We don’t want to inflate our project schedules needlessly, but we don’t want to schedule so tightly that we end up always running over-schedule.
This is slack for a project schedule, but slack for an individual is a bit different. A person’s slack time derives from under-utilization, which is to say, if someone is scheduled to work 40 hours a week, but they only have about 36 hours of work and meetings, then they have about 4 hours of slack time.
There are a number of ways those spare hours could be used.
- You could think of them as contingency, much like how we build slack into a project. For the individual, this lets them still work within the 40 regular hours of the week even if a task or two takes more time than anticipated.
- You could reinvest them into your employees’ professional development, giving them opportunities to research and learn and improve.
- You could encourage your employees to spend time together, contributing to improved team development and subsequently productivity.
No matter how the hours are used, they’ll result in reduced stress, which contributes to improved health, reduced absenteeism, and higher productivity. But we do want to make sure those hours aren’t completely wasted by reading Reddit, shopping, scrolling through Facebook, or any other activity that doesn’t really relate to work.
The method of channeling this time has to be subtle and cultural rather than autocratic. Encourage team members to work together and spend time getting to know one another, or to pursue projects or learning that aren’t directly related to what they’re working on right now. If you try to schedule the slack time, it’s no longer slack and starts becoming stressful. Remember, when necessary, this time becomes contingency to help the employee to not have to work more than 40 hours a week. If you schedule extra activities, it’s no longer slack.
The reason this is important is that slack time is used for reinvention. It provides us an opportunity to step back, reflect, identify new opportunities, and develop strategies for pursuing those opportunities. If we don’t have time to do these things, then we cannot improve our business or the way we work.
What’s more, humans struggle to work more than 40 hours a week, especially for a prolonged period of time. If your staff are working 45 or 50 hours a week, it will significantly impact their productivity and output. After a few weeks at 50 hours, their output will likely be equivalent to someone working around 32 hours, except their mental, emotional, and physical health will be worse than someone working only 32 hours. And on top of this reduced productivity, they won’t be investing time in reinventing how they work.
Just like when walking on a slack line, managing our work schedule requires balance. But it’s more science than art in this case: estimate your tasks, and then build the schedule so people have a reasonable amount of time to get things done, plus an extra 10-20% of slack to provide contingency and opportunities for team building and reinvention.