Novelty rules at The Open Book

  • Opinion
  • November 7, 2018
  • Hayden Glass
Novelty rules at The Open Book

Secondhand bookshop The Open Book in Ponsonby is in the process of being restored to commercial success by a group of new co-owners who all happen to be economists.We're sharing some vintage stories from its journey so far. Hayden Glass considers the lure of novelty.

We have been looking recently at the question of what types of books sell best. We have no shortage of hypotheses. But every book and every sale are unique and there are many genres and many rooms. The age of the book, its condition, its price, its position on a shelf, the appeal of its cover, and whether the author is well-known all seem likely to be relevant somehow. The number of potential variables make it hard to do the analysis, let alone find any general guide.

Now we think we might have found one useful rule, inspired by some excellent investigations done by our bookstore manager. Because it seems that how recently we processed a book into our stock is associated with how quickly we will sell it.

Be prepared, this is quite a long story. You might like to get a cup of tea.

Here is the track of the 503 books processed in to our stock in August 2017. This shows the proportion that we sold in that month and the following 12 months. You can see that in August itself we sold 9 per cent of them (45 books) and by August 2018 we had sold nearly half.

Ageing out

We can see the same effect in a different way by looking at the age of the books we sold in a single month. The chart below shows the time of processing for the 642 books we sold in August 2018 that we can track.

You can see that books processed in August 2018 itself made up 17 per cent of revenue in that month, books processed in 2018 overall made up 72 per cent, with books processed in the two previous years accounting for the other 28 per cent. (The stock we bought when we bought the store is all labelled 2016 in our system.)

This greater saleability of more recently acquired books is not because there are more books from 2018 on the shelves. The next chart repeats the proportion of sales (in maroon) for August 2018 from the previous chart against the proportion of stock (in blue) from that time.

Books processed in August 2018 made up only six per cent of stock. The effect (more recent books accounting for a disproportionate share of sales) is consistent by year, with stock from 2016 accounting for 16 per cent of August 2018 sales but 63 per cent of stock. You can also deduce that we have processed a lot more books so far in 2018 than we did in 2017.


The proportion of newly-processed books that are sold varies from month to month. Here are the tracks of the 10,082 books processed into our stock between August 2017 and March 2018, showing the proportion sold in the following months. I have made it a line chart for ease of reference, with each month a separate line.

You can see that we have sold somewhere between 35 and 60 per cent of books six months after processing. The worst performing batch of books (the bottom line in the chart) so far have been the 503 from August 2017 (the first chart above). The best performing so far are the 768 from November 2017.

The orange line on the chart is the result of averaging all of those tracks into one, ie, the proportion of books that we would expect to sell of any new batch we processed in the months after they appear on our shelves based on our history so far.

Using this average, a newly processed book has a 27 per cent chance of being sold in the first two months. The chance of sale grows much more slowly each month after that. After six months we will have sold about half of the books.


I don't know yet what is driving this effect. It could be that these books are just more saleable (more what people are looking for, in better condition, priced and displayed better). This would mean that what we are seeing is just be the result of sorting through all the books by our customers, taking the appealing ones and leaving the others.

The chance of sale per month does not seem to reduce when we process more books. This means that we generate more revenue from newly processed books when we process more of them. The last chart shows the revenue earned after six months from the books processed between August 2017 and March 2018, ordered by the number of books processed in each month. The months when we processed the most are on the left. The yellow line shows how many books we processed in each month, against the right-hand scale.


It seems likely that processing books increases sales overall. But I guess it is theoretically possible that customers buy the same number of books they would anyway, ie, they buy newly-arrived books if they are available but otherwise they make do with what they can find. Just eyeballing the numbers, I can not see an obvious correlation between the number of books processed and total sales in a month but there are a lot of influences, so it might be something to come back to with a more formal mathematical approach. We can also look at books processed by genre, look for situations where we processed a lot of books in a particular genre in a month, and see what happened to sales in future months.

An alternative to either of these would be to do a test, ie to process a lot more or a lot fewer books for a month (enough to show up in total sales) and see what happens. If we process 1,000 books we would expect to see roughly 270 sales in the subsequent two months.

If sales of newly-arrived books are entirely additional, then total books sold would go up by 270 over two months, which is around 20 per cent. Of course, we couldn't be completely sure they were additional sales, but at least it would give us a bit more information to work with.

I will keep you posted.

This story originally appeared in September 2018 on The Open Book's blog.

​ ​

This is a community discussion forum. Comment is free but please respect our rules:

  1. Don’t be abusive or use sweary type words
  2. Don’t break the law: libel, slander and defamatory comments are forbidden
  3. Don’t resort to name-calling, mean-spiritedness, or slagging off
  4. Don’t pretend to be someone else.

If we find you doing these things, your comments will be edited without recourse and you may be asked to go away and reconsider your actions.
We respect the right to free speech and anonymous comments. Don’t abuse the privilege.


Human nature: How treating pets as people is driving a retail boom

Demographic changes have shifted the way New Zealanders treat their companion animals. Kiwi shoppers increasingly want to treat their fur babies to a human-like level ...


Here comes the girl gang: Paris Georgia to open New Zealand Fashion Week 2019

Many players in the fashion industry are currently engaged in rewiring their processes to match changing customer expectations around speed and access, but Paris Georgia ...


Mergers: Making it work

  • News
  • August 17, 2019
  • Jai Breitnauer
Mergers: Making it work

We took an in-depth look at recent retail mergers. Jai Breitnauer compiled all the advice from the feature into this handy guide on how to get one right.

Read more

Social scoreboard

Zavy and The Register have worked together to create a scoreboard that compares how the top 25 traditional media advertising spenders in New Zealand have performed on social media over the past 30 days, updated in real time.

Concept to closet
Business coverage of New Zealand Fashion Week.
Regional rollercoaster
What does retail look like in 2019 for ...
Town centres
A positive retail environment over the past 12 ...
Amazon Arrival
Keeping up with all things Amazon as it ...
The Retail Yearbook 2017
As we battle our way through the busiest ...
The future is bright
We spoke with four retailers in their twenties ...
Hospitality enhancing retail
Some think food and integrated hospitality offerings will ...
Spotlight on signage
At first glance, the humble in-store sign might ...
Red Awards 2016
The Red Awards for retail interior design celebrate ...
Auckland Unitary Plan
Auckland is changing. The Unitary Plan will decide ...
How to open a store
Sarah Dunn considers what it would take to ...
All things to all people
Kiwi retailers share their omnichannel strategies.
Rising stars
Retail's top young achievers.
Delivering on your promises
The sale isn't over until your item is ...
Retail in heartland New Zealand
Retailers keep the regions pumping, but how strong ...
Women in retail help one another. We spoke ...
The changing face of retail
Shifting demographics are creating big changes in New ...
The retail yearbook
With the help of experts in the retail ...
Retail rogues
We put the spotlight on staff training. Jai ...
Here come the giants
Topshop has arrived in Auckland’s CBD, David Jones ...
From retail to e-tail
Ecommerce has become part of the way mainstream ...
Loyalty in the digital age
How are retailers maintaining loyalty? Sarah Dunn, Elly ...
Window shopping: A spotlight on social media
Sarah Dunn and Elly Strang look at how ...
The Innovators | In partnership with Spark Business
Technology is rapidly changing the retail industry as ...

Mergers: What about the staff?

  • News
  • August 16, 2019
  • Jai Breitnauer
Mergers: What about the staff?

As part of a recent look at retail mergers, Jai Breitnauer considers their effect on staff.

Read more

Walk Ethical: The new way to commit to providing a better workplace

  • Sponsored content
  • August 15, 2019
  • Sponsored content
Walk Ethical: The new way to commit to providing a better workplace

Colmar Brunton recently reported that over 90 percent of Kiwi consumers would stop buying goods and services from businesses found to be unethical. Walk Ethical is the new accreditation available for business to show they’re dedicated to ethical standards in the workplace.

Read more

Are you on The Retail Hotlist 2019?

Join us in celebrating the vitality and innovation of New Zealand’s retail sector by voting for The Retail Hotlist. The NZ Retail team and Gem, ...

Next page
Results for
About us.

The Register provides essential industry news and intelligence, updated daily. And the digital newsletter delivers the latest news to your inbox twice a week — for free!

©2009–2015 Tangible Media. All rights reserved.
Use of this site constitutes acceptance of our Privacy policy.

The Register

Content marketing/advertising? Email or call 022 639 3004

View Media Kit