How long will this take?
Everyone uses story points and everyone struggles through story points. Using ideal days makes it easier to estimate and get on with the work.
In his book Agile Estimating and Planning, Cohn (2010), described two ways of estimating - story points and ideal days.
Story point estimation is about relative estimation, the size of a story compared to others. I believe it has its place. It works well when there is a cross-functional team working on a platform that they have had previous experience.
A new team working on a new platform will take a few sprints to get used to the environment and hard to get predictability in the beginning. Once they have worked on several sprints then they can start getting predictability in their work.
Another challenge with story point estimation is that most people subconsciously tie points to the effort involved as opposed to its complexity compared to other stories.
Using ideal days is my preferred method. It’s a more intuitive approach.
It stimulates discussion within the team just like the story points. It highlights the variability in the experience of the team members. One person's 2 ideal day may be another’s 1 ideal day.
I think it is ideal for teams that code in different languages but are not cross-functional.
There are some challenges with ideal days. Which are just challenges with estimating overall whether it’s story points or ideal days.
people tend to be over-optimistic
different skills and experiences will have different estimates
teams do not have complete information
How to estimate using ideal days, assume:
the story being estimated is the only thing you are working on
you have everything that you need on hand
there is no interruption
One aggregate estimate for the story, don’t split it by roles or teams (for example one estimate of 2 ideal days for the developer, 1 ideal day for the tester - have 3 ideal days to complete the story).
The Agile ceremonies remain the same, it’s these ceremonies that will help refine the estimates and the plan.
During backlog grooming, the team gets to improve their understanding of the requirements, refine the stories. They also start to see how the stories fit into the overall features and epics. They can start sizing them. And may only need the grooming session to size them.
In sprint planning, the team pulls in the stories from the backlog, plans the sprint, and synchronise the work. The estimates may be refined, if required. During the daily stand-up, it’s not about refining the estimate but synchronising the daily work.
Ideal days is a more intuitive approach to estimating for Scrum teams. Give it a go and see how your teams perform.
Practice
Discuss with your team on trialling ideal day estimation. If they’re using story points, ask them whether they would do ideal days on one sprint or use ideal days in parallel and see how they go.
Do they feel it’s more accurate? Is it easier? How close were they between the estimate and the actual effort?
Recommended Resource
I’ve recommended Mike Cohn’s book before. It is such a great book on Agile delivery.
My Resources
Below are some of my free resources if you’re new to project management.
Paid Resources
Simple and Effective Project Risk Management - for those new to project management. It will teach you what you need to know and get you started quickly.