AboutSteve Wilkerson Expertise annual fund, direct mail, capital campaigns, consultants, major gifts, fundraising planning, case statements, prospect research,
Experience 35 years as senior development officer of significant recognizable instititutions in education, healthcare, academic medical centers, colleges, universities, churches, synagogues and general fundraising consulting.
Question My organization is purchasing a new database (Income Manager) and I'm trying to figure out how to build a query to find out our donor attrition rate. As a first step I need to simply know the mathematical equation to get the attrition rate -- separate from any database question. I think it's some division with lapsed versus active donors but ?
We define "active donor" as a donor who has donated within the current or past two calendar years. i.e. has donated since January 2002.
We define "lapsed donor" therefore, as someone whose last donation is earlier than the past two calendar years. So someone whose last gift was in December 2001 is lapsed.
Can you tell me how to calculate attrition rate? If you can also tell me how to get that out of Inocme Manager, even better.
Thanks in advance.
Answer Kim,
Does this help?
For any attrition rate, you want to understand what % of
your base continued to give, based on certain assumptions.
With an assumption that allows for 2 years of giving to be
counted as "current", the attrition rate will be skewed from
a more pure calculation but the logic is the same. First,
take a base time period (in your case, use January
2000-December 2001) and calculate the number of donors you
have in that period (say 15,000). Then, take that same
group and determine whether these 15,000 gave in the second
time preiod for the period January 2002-December 2003 (let's
say that 10,000 made an additional gift in that period).
Your attrition rate is the difference, devided by the base
number (15,000 - 10,000 / 15,000), or 33%. Keep in mind
that this doesn't account for growth in the pool; you are
simply trying to calculate the number of current donors from
the pool of former donors in your first base period.
Ordinally, you'd use a one year period, but so long as the
two periods are the same, the logic works the same.
