I find myself frequently faced with Scrum teams that include team members that are “50%” dedicated to the team. In many instances, I see this as an incredible waste of time and resources. First, let’s cover the necessary ground — Scrum does not “require” full time team members. Agile Software Development with Scrum (Schwaber & Beedle, 2002) specifically discusses part-time team members.

However, my experience with teams that have part-time members is usually disappointing. Here’s why:

1. Team members that are shared by one or more teams find themselves doing time-wasting multi-tasking that lessens the amount of productive hours they have in any given day (see The Mythical Man-Month for more information here). A developer, working on just two teams, will find themselves in the act of re-engaging in a task for Team A or dis-engaging from a task for Team B for more than an hour everyday. In his book Slack, Tom Demarco also presents a strong case against part time team membership, noting that it often results in significant frustration for the team and the individual
2. Part time team members cannot attend every daily Scrum, every Sprint Planning meeting, every Sprint Review meeting, and every Sprint Retrospective meeting. This doesn’t even include the various group design discussions that can be expected within a Scrum team. Some managers even suggest that the part time team member doesn’t need to attend every meeting — “it would be too many meetings and, besides, they’re only part time, right?” But if a team member misses many of these meetings, is he really part of the team? Is he collaborating effectively with the rest of the team? How many daily decisions are delayed or deferred because of the absence of the part time team member?
3. Part time team members swell the size of the Scrum team. I’ve even had managers us mathematics to tell me that seven full time members and four part time members, is really only a team of nine (rather than eleven). Sorry folks, that kind of math doesn’t work here. When (if I’m lucky enough) to have all of the team present for a team meeting (like, for instance, backlog grooming), I don’t have half-people there, I have eleven people (one head, two arms, two legs a piece). That many people will have a very difficult time reaching consensus and, in the end, most team decisions will be harder to attain because of the excessive size of the team.

To be fair, part time team membership makes a little sense in a couple of situations. First, if the team member possesses a very unique skill set that most teams need from time to time (like a customer documentation writer or a database architect), attaching a member on a part time basis makes sense. Second, an employee can be attached to a team temporarily to provide training to full time team members (spreading the knowledge, cross-training). In both instances, however, the “attached” part time employee is fulfilling a specific need on a temporary basis.

My position, therefore, is that Scrum team members, except in those instances where part time assistance is needed on a temporary basis, should be full time members of the Scrum team. I rarely see permanent part time membership as effective and, frankly, it’s usually used as a stop gap measure against a lack of skills in a certain area — but with no short-term planning to address the underlying problem: the skills issue.

Avoid having part time team members on your teams. You’re more than likely better off telling management, “Thanks, but no thanks.”