What Does Dunbar’s Number Have to Do with Your Donors?

How many donors and prospects a major gift officer or other professional fundraiser should have in their portfolios is a moving target and while there isn’t an exact science to making that type of decision, for many years I have recommended development personnel consider “Dunbar’s Number.”

What is Dunbar’s Number?

 Anthropologist Robin Dunbar has suggested that the average person can only manage about 150 authentic relationships in their lives. There are varying degrees of connection with these individuals, but the typical breakdown, as Dunbar describes it, is:  

  • 5 inner core friends

  • 10 very close friends

  • 35 good friends

  • 100 other friends

 I share this data not to suggest that 150 individuals make for a good portfolio size — that seems unreasonable — but highlight that at some point the number of connections in your professional fundraising portfolio becomes inefficient and ineffective. The challenge that many development personnel faces is determining just how many donors and prospects max out the benefits of their portfolio without over-stretching their capacity.

Using Dunbar’s Number to Optimize Major Gift Officer Portfolios

Dunbar claims that an individual can manage 150 authentic relationships — meaning a total of 150 both in their professional life and in their personal lives. While professional relationships can lead to fundraising success, personal relationships are critical and must be accounted for. In my experience — using Dunbar’s number as a foundation for my recommendations — I suggest full time gift officers personally manage no more than 75 donors and prospects. 

Let’s adjust Dunbar’s categories to better align with fundraising work:

  • Inner core ⟶ Solicitation

  • Very close friends ⟶ Cultivation

  • Good friends ⟶ Qualification

  • Other friends ⟶ Stewardship\Yet to qualify

 At any given time, a full-time gift officer should have:

  • 3 people to whom they have actively solicited and are awaiting a response

  • 5 individuals they are actively cultivating and waiting to solicit

  • 18 people who they have yet to qualifying 

  • 50 individuals they are stewarding or have yet to qualify.  

Quality Over Quantity to Maximize Impact 

 While that doesn’t sound like a large pool of donors and prospects, remember this is an exercise in quality over quantity. Allowing Major Gift Officers to focus on a smaller pool of connections enhances effectiveness and efficiency. Northwestern University put this to the test and increased the number of dollars raised by nearly 600%! (Source) If your organization is looking to improve your efforts, start by analyzing your team’s portfolio sizes and be strategic about the number of connections each individual is responsible to maintain — the number may be too high, preventing the formation of authentic relationships, in turn impacting the success of fundraising efforts. 


About the Author

Michael J. Buckley, CFRE is a career fundraising professional and Founder and Managing Partner of The Killoe Group. His firm assists nonprofit organizations increase revenue, exposure and capacity through smart, data driven, successive decisions and effective planning. Mike’s experience and passion for the profession of fundraising have made him a sought-after speaker, consultant and presenter. The Killoe Group’s broad experiences include annual campaign audits and management, capital campaign leadership, feasibility studies, interim program leadership, board governance, strategic planning and capacity building.