Kanban and Scrum... so whats the difference?

I've been asked this question several times by people who have just started becoming interested in agile project management, so I figured I could write a blog post explaining some of the differences.

Both Kanban and Scrum can be described as project frameworks or project tools, as such they limit the wielders options into working on the project in a particular way.

So what are the similarities? Both models can be described as agile frameworks that require the organization to divide into smaller, cross-functional teams that require self-organization. The work in both systems there the workload is divided into smaller, concrete deliverables and planned in short iterations where release of the product and product process is optimized by working alongside the customer.

The framework that scrum provides is more extensive and is therefore described as more prescriptive than Kanban. Conversely, Kanban is called more adaptive and follows fewer rules, for instance not advocating the use of time boxed iterations like Scrum does. Generally speaking however, both methods are considered more adaptive overall.

Another difference showing the more adaptive nature Kanban has over Scrum is the fact that it doesn’t have any assigned roles unlike the three roles of the scrum master (Product owner, scrum master and team). Scrum teams measure velocity, how many items are done per sprint (iteration) on average and attempt to limit their work according to the same velocity. Kanban however puts a limit to how many items can be worked on simultaneously when dividing tasks between various workflow states. These limits set for desired velocity in sprints or number of tasks allowed in workflow states is decided individually for each project and preferably through experimentation in seeing how many tasks that can be handled. That is just brushing the surface of all there is to it, but as with all agile project management, lets keep the documentation light, shall we?

Give your opinion down in the comments what you think are the greatest differences between the two!