It's still true! The more recently a book has been processed, the faster it sells.
This graph shows the number of books processed in the 12 months to August 2021. The blue is the number that were sold within six months of when they were put in stock, the orange is the number sold within 12 months. The grey is the number that remain in stock as at early February 2022.
You can see that the blue areas are bigger than the grey. It turns out that on average we sold about two thirds of the books processed in the year to August 2021 within six months, a bit better than we were doing before.
The blue areas are are much bigger than the orange, even though they are both six months long. Translation: a book is much more likely to sell in its first six months in the store than in its second six months.
First time's a charm
The next graph shows how, with each passing month, the odds of a book selling fall.
On average for the twelve months from August 2020 to August 2021:
We sold 17 per cent of each batch of books in the month that they were processed in to stock. Sometimes books are processed later in the month, which can mean there aren't many days for people to spot them.
We sold 22 per cent in the month after their arrival, and another 18 per cent in the next couple of months.
By the time a batch of books has been in stock for six months, you can see that the chances of one of them selling has markedly reduced.
As I have said before, it isn't because there are a lot of newly arrived books and somehow they dominate the shelves. We have about 15,000 books in the stocklist and have been processing about 1,000 books a month in. So the latest books only make up about seven per cent of stock.
Put another way
Because of this effect where the most recently arrived books sell faster, books from the last six months make up fifty to sixty per cent of revenue in any given month. It also means that stock turnover is a big driver of revenue and processing more books each month should boost revenue overall.
Alas, processing more books is easier said than done. The volume of donations coming in, our storage capacity, our staffing, the physical space in store, and the time taken by all the other things we need to do each month all influence how many books can be processed. That said, recent progress has been good. In January 2022, we processed over 2,000 books in a month for the first time. We sold 17 per cent of those books that same month, and another 15 per cent in February.
Why newer books sell faster remains a mystery. One contribution could be that lower priced books sell faster, and so as the lower price books from each batch are picked over, there are fewer cheaper books in older batches left on the shelves. There is some evidence for this. The data shows that average revenue per book sold in each month's batch typically grows over time, by about 20 per cent after six months.
Other explanations are more mysterious. A fellow bookstore owner observed to me a while back that any book that he had recently touched was more likely to sell. Something as simple as tidying up a shelf apparently sends out an invisible call to customers. The dust of desirability perhaps.