# Calculating frequency of client visits.

• Oct 3rd 2010, 08:48 AM
benjamin
Calculating frequency of client visits.
Hey guys, Hopefully someone can help me with this probably very simple math problem.

I am trying to find a calculation for calculating the frequency of client visits to our business. I am looking at two things. The average number of weeks clients leave in between their appointments until they come back and see us. And how many times they visit us a year.

For example:

ClientA visits every 6 weeks, and so comes in 8.6 times a year.
ClientB visits every 4 weeks, and so comes in 13 times a year.
ClientC visits every 10 weeks, and so comes in 5.2 times a year.

The average weeks left between appointments for all clients (6 weeks, 4 weeks, and 10 weeks) is 6.66 weeks.

The average visits a year for all clients (8.6, 13, and 5.2) is 8.9 times a year.

The Problem

When I work it back and take the two averages it doesn't work. A client visiting every 6.66 weeks would visit 7.8 times a year. yet the average I got was 8.9.

Can somebody please explain why this is?

Many thanks,

b
• Oct 6th 2010, 08:21 PM
raphw
Because your messing with the average numbers. If you had 52 clients and only one of them was seeing you every week while the others were never seeing you: The avergae client would visit you once a year while you nevertheless have someone coming to your place every week.

In formula:
$\frac{52/a + 52/b + 52/c}{3} \ne \frac{52}{(a+b+c)/3}$

a,b and c represent how often a year some of your clients visit you.