Fundraising metrics calculation class

This module defines the FRMCalc class used for doing the actual calculations of each of 11 metrics.

calc = FRMCalc()
second_gift_conversion_rate = calc.second_gift_conversion_rate(acquired, second_gift)

The number of donors who gave this year compared to last year.

The number of donors who have given a second gift in a given time period.

How much it costs to aquire a donor. This metric is generally most useful when evaluating acquisition campaigns.

The percentage of donors from last year who did not give this year. Essentially the inverse of Renewal Rate.

The percentage of donors who gave last year and again this year.

The average gift in a year or campaign. You probably already track this one.

The middle gift from a given set of gifts. Useful to see in tandem with average gift, as average gift can sometimes be skewed by a large gift.

How much it cost to earn a dollar in revenue. A number less than a dollar would indicate profitibility, and a number more than a dollar would indicate loss.

The revenue from a campaign or time period less the cost. This is another one you probably already track.

Another way of looking at income vs. cost, this time looking at the revenue earned for every dollar spent.

This one is fun. The average value of a donor acquired in one year over a given time period.

The list of metrics calculated, along with the formulas, is derived from the booklet "Know Your Top 10: 10 Commonly Used Fundraising Metrics Explained]" by Harvey McKinnon Associates.