Slack Time in Project Management

Slack Time in Project Management

If you manage an Agile team, your responsibilities don't only involve reaching an established goal but managing the project's timing. To plan effectively, you have to anticipate the unexpected.

However, at least one thing will go astray in many cases, or something you didn't plan will happen. That's probably the worst nightmare for all project managers.

During periods of imbalance, many PMs resort to slack time, a helpful tool that enables project flow without any significant disturbances. Now, let's see how this works and how you can benefit from slack time.

What is slack time?

Slack time is often defined as the amount of time you can delay the task without interfering with another task or affecting the completion date of your project. As we mentioned earlier, this happens when flow becomes unbalanced.

Usually, imbalance occurs when some team members finish tasks before the rest of the team. It can also happen when there aren't enough tasks to keep everyone occupied, a team member gets sick, a demanding client pulls some team away, or some procedures need more testing and research. These factors can contribute to an overall imbalance.

Therefore, project managers need to have a couple of ideas up their sleeves to cover unexpected situations. When you are faced with slack time, you will always have a solution to fit your team members' needs and meet the project deadline.

Do you know how to use slack time in the best possible way? There are two factors to consider when making this decision. Firstly, you need to focus on your project goals. You can use the slack time to work on tasks that will help you complete the project before the deadline.

Secondly, make sure to listen to your team when they suggest how to use the time. This will remove some burden off your shoulders and offer your team members a strong sense of autonomy and ownership.

What does slack time indicate?

As previously mentioned, slack time indicates the amount of time a task can be delayed without affecting other tasks. Many will refer to slack as "float" as well.

Slack time is an integral part of project management and project processes, for that matter. Therefore, you need to display it clearly on the PERT chart. Choosing to ignore slack time may cause consequences that could compromise the entire project and its efficiency.

Only when you can identify the slack time can you use it to your project's advantage. On the other hand, if some of the activities already have slack time that can be delayed, you can divert resources elsewhere and use them for more pressing activities.

How to use slack time in project management?

Slack is important to the project manager for several reasons. It indicates how much you can delay an activity, beyond its earliest date, without affecting project completion time. It's important to mention that you can apply slack time only to those activities that don't lie on the critical path of the PERT chart.

For the activities on the critical path, the earliest time equals the latest start time, and the earliest finish time equals the latest finish time. Calculating slack time is a crucial part of project management.

All tasks located on the other paths of the PERT chart will have some difference between the earliest start time and the latest start time, as well as the earliest finish time and latest finish time.

This difference isn't accidentally placed here. It's used to estimate how much we can delay activity while allowing other activities and projects to be finished according to schedule.

On the other hand, you must complete activities on the critical path without delay; otherwise, they will postpone the completion of the project.

What to do with slack time?

Many project managers want every spare moment of their free time filled with work, but we are firmly against it. Slack time isn't only about flow's self-balancing mechanism; it's a tool that helps us work efficiently and effectively while occasionally blowing off some steam.

It's not natural to work all the time; you may burn out and become stressed. Even though being productive is a great thing, all productivity methods say that we need some time for ourselves. Most importantly, these breaks help us to focus on several things.

For example, mental breaks are significant because they allow us to process information, store essential data in our short-term memory, and regenerate so that we can focus on new tasks.

If you have some extra slack time and no scheduled task, don't freak out. Add a slack time card to your board and fill it with a defined activity. Or you could take a break and spend some time learning new skills.

Unfortunately, many of us take too much work instead of cooling off. This will eventually kill our happiness and cause burnout. Slack time is priceless, especially when we can leverage it to our team's advantage.

We can also apply slack time on the task we would normally dodge, or spend this time brainstorming new ideas. Slack time is highly beneficial because it allows us to increase our team's efficiency and processes.

How to calculate slack time

Do you know how to calculate slack time? It's quite easy, and it doesn't involve any complex calculations. To calculate slack time accurately, you need to determine the earliest start time for the project, establish the latest start time, and then find the difference.

We need only two things:

  • ES – the earliest time to start with the activity
  • LS – the latest time to start with the activity

The formula goes like this: Slack Time = LS-ES, and that's it.

You can also calculate slack time as the difference between the latest finish time and the early finish time. Make sure to apply this calculation to all activities in the project.

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