In a continuing vein of scholastic research, let's plumb again the employer-employee relationship, only this time let's evaluate the number of people in any hierarchy.
I have a general rule of thumb about staffing a team or a project. I usually estimate the amount of work to do and how long it will take to accomplish given a certain number of people involved. Then, with years of experience behind me to guide me, I add 10% more time and subtract 10% of the resources. Why? Even if I kept all the people I originally estimated on the team, we'd still end up taking longer than anticipated. I dealt with some of the reasons in my post Sunny Day Scenarios.
Note though, that I am advocating making your team, your hierarchy, your organization as small as possible. That's counter-intuitive in a time when we are evaluated on how large a team we manage. Frankly, I'd rather manage a smaller team that has greater focus and higher commitment. I guess it's a question of guerilla tactics versus the armed frontal assault.
Why are smaller teams better than larger teams, most things being equal?
1. Focus - a manager can spend more time with each person on a smaller team as necessary.
2. Clarity - in a smaller team, everyone has a line of sight to everyone else. Everyone is aware of the circumstances, the successes, the failures and the expectations.
3. Cohesion - smaller teams have a greater chance to be more cohesive. (The corollary here is they also have a better chance of tearing each other apart)
4. Administration - I need to recruit, train and bring fewer people up the learning curve, so we spend more time on real work and less on the administration of the team
5. Interaction - I can interact more easily with each individual and gain a sense of their commitment level
6. Visibility - Since it is harder to "hide" on a small team, I can quickly weed out those who aren't up to snuff or just aren't bought in to the program.
There's one other one as well - esprit de corps. Belonging to a small, elite group who share common goals and work together effectively reinforces a group bonding and culture.
Many of you reading this will scoff - with a larger team I can always throw more bodies at a problem. Well, no, not really. As I add people to a problem there becomes an issue of dimishing marginal returns. Eventually I add enough people where most of them simply get in each other's way. As the team gets larger I have to lower my standards for the people in the group to continue to add people to the team. I have a greater chance to bring aboard folks with less commitment and less loyalty. As I bring more people aboard I have no line of sight to each team member and have to begin to place individuals who job is just to manage others in between me and the rest of the team. At that point, I'd better be a project management expert, and so had all the other folks in the chain of command, because culture, communication and team loyalty aren't going to be the big drivers to bring a project in on time.
I understand in some circumstances it's simply not feasible to have a small team on a project, but I will encourage you to keep the teams in anything you do as small, as focused and as cohesive as possible.