This is one of the great debates! But the answer is not always black or white in reality.

Let’s look at the value we get from an estimation process:

  1. Everyone understands the work at hand and any complexities
  2. We get an idea of any issues or risks that could impede this work
  3. We get an idea of dependencies required inside or outside of our system

For me, these three things are the most important pieces. The understanding, alignment and management of things that could impede us.

The fourth thing we get from estimation is the number…. It is natural that everything we do will have some need for a forecast, we cannot run our companies on hopes and prayers.

But there are different ways in which we can forecast.

In one of my previous blogs, we took a look at separating out different work item types. This is your first step to be able to understand how long pieces of work are taking to move through the system.

Now we have this view of different types of work, we can see how much variability there really is. For example, below is a control chart showing just user stories.

You can see that 85% of the time stories will be completed in 8.71 days. You can also see there are some real outliers around 20-35 days. This is a great signal to spend some time investigating and finding out what caused that to be much higher than the rest. The more of these you have, the more opportunity for process improvement. The 85th percentile is really just a confidence factor and you have a choice to change this number. But if I said you had a 85% chance of learning something from this article, you would probably be happy and keep reading.

I would have one of these charts for each work item type. You will soon realise if something crazy is going on and it will allow you to ask questions. For single piece flow we could also give our customers expectations of how long work is taking.

What this chart doesn’t show you is how this is changing over time. This is also important! Are we trending up or down?

So you can produce charts like the above to show this. In the same team you can see this has been trending down in the last 3 months. That could be for a number of reasons, the key is these charts don’t give you the answer, but it prompts you to ask the question and find out the story. You are looking for improvement and stability. If you can have both at the same time 🙂 There are also many views of this data in different charts to give you some forensics. I have just shown you two.

What I have shown you has very much been at team service level. Forecasting is not limited to just here. When we first create options in our companies we also need a rough view on size. In one company I partner with we have T-shirt sizes. So an XL is 16 weeks. A rough cut of size and will be refined all the way through the delivery. But it gives them something to hang the roadmaps on.

So back to my original question.

Myth…

We do understand the size of the work. But this is based upon historical data by work item type, and we accept that this is not perfect and changes as we and the system changes. We still have conversations about the work, but we might say ‘Can this work be done in 10 days or less’ using the data to determine that number.

We continually monitor to understand variations and causes for our trend line changing. This could result in process improvement inside or outside of the team.

But remember the first principle – Start with what you do now! I am not saying throw all current processes out on day one! But be aware there are other options, and maybe start looking at this stuff behind the scenes. That’s what I did and over time I stopped using the other ways.

You might have also heard of Monte Carlo modelling. Other people do a far better job than me at explaining this and so worth checking out this video from Sonya or Troy’s Website.

So next time you crack open your online tool, have a look and see what your data is telling you!

You will learn more about these charts on my Kanban System Design Course. Equally if you just want to have a chat. Reach out to me.