Relative sizing of tasks and individual thought process
Scrum is largely hinged on estimating the size of a task using effort rather than time.
For me this largely makes sense, particularly when sizing PBIs\Tasks where time is difficult to calculate.
I think having pre-defined stories and associated effort is great for relative sizing. By doing this it helps in achieving some consistency and consensus across the sizing process. However, how each person applies these stories in determining the effort is an individual process based on individual knowledge and experience.
I’ve heard people say that time should not be considered in any way during scrum sizing. But the following are my thoughts on the matter…
Someone who has little knowledge or experience in an area will simply use "gut feel". They will apply their intuition and determine how the PBI being sized compares to the pre-defined stories. And this works well for them.
However, someone who is confident in how long each of the pre-defined stories have taken to complete and how long the PBI being sized would take to complete (based on experience), can use this information during their evaluation. In this case, time is one of many pieces of information being considered in helping them compare and size. My thoughts are the more information a person can consider, and the more experience they can draw from, the more accurate the size will be.
What are your thoughts on this? Is it a sin in scrum for an individual to consider time, along with other factors, when comparing and sizing a PBI?
the more information a person can consider, and the more experience they can draw from, the more accurate the size will be
Yes I think so too. And also take into account the Risk factor, and the Unknown.
By sharing this in a open way, other team members, with less experience, can learn from this, and thus improving as a team. In my "poker sessions" we always focus on explaining, so anyone can learn.
Is it a sin in scrum for an individual to consider time, along with other factors, when comparing and sizing a PBI?
No, I think it is not a sin, it is mandatory, as time is also part of your past experience(s).
The beauty of relative sizing and having everyone on the team determine their own size is that everyone can do it based on the information known to them. If sizes vary then discussion ensues. If all agree on a size based on their knowledge, then move on.
The discussion will often bring out that one or more persons have experience and provide new information to the rest of the team. Sometimes that experience increases estimates, other times it decreases. Sometimes two people will have opposite experience which could help the team come together with a "middle ground" estimate.
Having different methods is not a bad thing. I coach people to estimate based on what they know at the time of estimating. Not all have the same knowledge but they can estimate relative to work that has already been done (information known) and relative to other queued work (guesses already made, also information know but not validated).