One of the messages I frequently find myself communicating is that most work sits in a queue much longer than it sits on a desk being worked on. When coaching people about the dangers of date-based commitments I like to point out that they will blast straight past the date by simply waiting to start the work. The amount of time a job takes is irrelevant when you fail in your commitment due to the work not being started.
On top of this, while there are frequent surprises that turn a 2-3 day job into a 4-6 day job, there are much bigger surprises that will turn a 1-2 week delay starting the work into a 6-12 month delay in starting.
This is why I asked “why do we [measure|estimate|rush|optimize|…] only this“… because so many organisations are myopic when it comes to work.
So prioritisation is important…
“The problem with any prioritization decision is [the] decision to service one job and delay another” – Don Reinertsen
Or as summarised in Focused Objective’s “Better Backlog Pioritisation” (written by Martin Burns, Don Reinertsen, Chris Matts, Joshua Arnold, Tony Grout, and Troy Magennis in 2016:
Doing one thing delays others
So instead of trying to just price an implementation, you need to manage the impact of the delays caused to other items. The only way to do that is to quantify the actual market costs of those delays.
Please also see a cautionary note from Black Swan Farming on the SAFe version of WSJF and check back with Don Reinertsen’s ‘The Principles of Product Development Flow’ for the original version.