We are starting to use Kanban and my boss just asked me a question, as one of two people with prior Kanban experience within the group, that I don't really know how to answer.
My previous experience and training with Kanban had developers pulling stories in from the backlog by priority, in our case that was the topmost card. However, my boss would like certain stories to go to the developers that have domain knowledge for particular areas. For example, let's say Joe has the most experience in working with Contracts and a contract story comes onto the board. He would like Joe to be the one to work on that particular story.
This, to me, feels a little "off" and could lead to some developers having significant extra work due to having worked in any given area of functionality. My previous experience with Kanban worked under the assumption that any developer should be able to pick up the next card and figure out what to do and that this practice would eventually eliminate any single functionality area experts and level out developer expertise over time. However, I can also see how using subject matter experts can help move a story through the process faster.
What is the most "Kanban" way of handling priority vs. expertise when it comes to pulling in the next story?
Every system I've ever worked with allows a little bit of developer-level of prioritization. If the next card has the absolute (top-down driven) priority, then you have to pick that card. Mostly, though, I tend to work in places where "these next 6 cards are up, pick the one you like". This gives the developer a little bit of room for type of work he or she prefers. Plus, it gives the developers a greater sense of ownership since they did get to pick (to some extent) the work they were doing.
Regarding your example, it's a little off base. In an ideal world any developer should be able to pick up any card. In reality, this isn't always true. If I give this project to Jim, it might take 2 days. If I give it to not-Jim, it make take all week. This is a sign! What information sharing is missing? How do you get the other developers to understand the Contracts component as well as Jim?
If the priority is a little bit gray, this stuff tends to work itself out. All the other developers know that Jim can handle the Contracts stuff. However, if Jim has no capacity, then someone else must take up the challenge. Kanban is supposed to alert you to blocked stories.