Updated October 2026

The answer first: one online shop's customers

Half of this shop's customers had gone quiet by month 14. The biggest drop came in the very first month: about 3 in 10 customers bought in one month only and did not buy again in the data. After that the line falls slowly.

The data are 3,978 customers of one UK online shop, in pounds, whose first purchase fell between January 2010 and May 2011. We called a customer "lapsed" after six months with no purchase. Six months is our choice, and a different rule would move the numbers. A customer who lapsed is placed at their last purchase month, the point where the quiet began, even though we only know it six months later. Customers still buying are placed at their last purchase month too.

What "still buying" means

Some customers had not gone quiet when the data ended. They are not lost. We just have not seen how their story ends. If we threw them out, everyone would look like a quick leaver. So the tool counts them for as long as we saw them. Analysts call this "censoring". Here, 1,961 of the 3,978 customers were still buying at the last look (49.3 percent). The other 2,017 had lapsed.

What the curve says

Out of every 100 of this shop's 3,978 customers, this many were still buying:

  • after 1 month: 71
  • after 3 months: 67
  • after 6 months: 61
  • after 12 months: 52

The line crosses 50 at about 14 months (the interval runs from 13 to 15). That is the "median": the time by which half have gone quiet. In all, 1,140 customers (28.7 percent) bought in one month only.

What to do with it

Ask where your own cliff is. If most of the loss is in month one, start there: look at the first order and what follows it. If your line falls slowly, the job is to keep your long-time buyers happy.

What this does not show

This is one shop and one group of customers. So we say nothing about which kinds of customers stay longer. It shows when customers went quiet, not why. Another shop, another season or another rule would give a different line.

Run it on your own customers

Upload a file with a time column and a flag for who has gone quiet, and read the curve and the median.

Run the free survival tool

Sources: Data: Chen, D. (2012). Online Retail II. UCI Machine Learning Repository. CC BY 4.0. A UK online retailer, GBP. Changes: customers grouped by first purchase month, January 2010 to May 2011; lapsed means six full months with no purchase.