David Brackin is the managing director of Stuff U Sell, the leading eBay trading assistant in the UK and a regular Tamebay contributor. Today, in the first of a three part series and the first published rigorous wide scale scientific test of eBay Promoted Listings, David sets out the basis for the experiments that Stuff U Sell carried out. Come back tomorrow when we will reveal the results of the tests and on Friday for the conclusions and actionable insights that you can use in your business.
Do Promoted Listings on eBay work? – The Trial
The “Promoted Listings” feature is now well-established on eBay as an additional paid-for service to market your listings. For anyone who hasn’t yet tried the service, it is relatively simple. You set up a campaign, identify the listing numbers you’d like to include and choose an additional percentage of the sale price that you are prepared to pay on top of the final value fee. In return, your listings compete to be shown in premium positions across the site – for example currently slots 1, 4 and 5 in the search results page are all promoted listings. The higher the percentage you are prepared to pay, the more likely you will appear in the top spot.
The benefits are clear. You only pay when you actually sell an item, and each sale then increases the sale history of the listing, so you can use it to give a kick-start to your best match position. Initially launched as a trial in 2015 and then expanded across further categories in 2016, I remember speaking with the product manager and being impressed by the idea but wondering one thing: will it work?
The inventory we have at Stuff U Sell tends to be one-off second-hand goods that we’re selling for other people, so the benefits of sales history don’t really apply to our listings, and in any case we relist our listings weekly to surf the Sunday wave of buyers. If it works for our listings then it will be a no-brainer for anyone else. We had run a few small trials and we noticed that we would always get some sales and pay some fees. However, sales move up and down each week at random so it might just be a rainy weekend and not the promoted listings that gave us the boost. How could we tell if we were going to get those sales anyway?
We were about to give up on Promoted Listings altogether when I spotted a book at the house of a friend who is a healthcare expert.
I learned how the gold standard of clinical research is a blind randomised test against a control group, and it was obvious this is what we needed to do with Promoted Listings. However, it wouldn’t be cheap to run the kind of extensive trial that would produce a definitive answer, so I asked eBay if they would cover the costs, provided we had independence to design it properly and share the results. They agreed and over the next week I’m going to share our results and what they mean for your business.
In clinical terms, we decided to test whether a “dose” of Promoted Listings spend would increase sell-through on a randomly selected group of our listings.
The trial would start with 13 weeks of no promoted listings (“zero dose”) to find our average sell-through rate how much it moves up and down randomly. This would enable us to use statistics to determine whether any effect was significant or just random noise.
Then over the next nine weeks, we would randomly select either all the even-numbered listings, or the odd-numbered listings or both and apply a “dose” of Promoted Listings to them and leave the other control group “untreated”. We chose PL dosages from 0% to 20%. Because we relist our listings every Sunday, the even/odd listings are jumbled up again each week, so each is a randomised half of our inventory unrelated to the previous week. We only applied the trial to our Buy-It-Now/Best Offer listings, not the auction format.
Furthermore, to make the test “blind”, my business partner was to pick which trial we were doing each week and not tell me, and I would analyse the relative sell-through rate.
The results were eye-opening. Come back tomorrow to see our initial findings.