The Reseller's Fallacy

Sean Gay - 3/30/2024

We've been doing it wrong

The discussion on the usefulness and accuracy of the eBay Sell Thru Rate (STR) as it’s calculated on the eBay app is one that always gets heated. Overwhelmingly, sellers agree that using the information found with the “Solds” filter is the best tool to calculate the estimated price and speed (STR%) of any given item.
I believe we all have been doing it wrong, YouTube has it wrong and it's time to call it out.
This is based on three ideas:
1. The eBay app calculated STR is a measurement of eBay’s success and is not applicable to individual sellers per the calculation itself.
2. The concept of the Gambler’s Fallacy as it applies to comping on the eBay app.
3. The effects of Confirmation Bias only positively support previous STR beliefs.  

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#1: The eBay app calculated STR is a measurement of eBay’s success and is not applicable to individual sellers per the calculation itself. 

Regardless of the method used to calculate the STR on the eBay app, the resulting percentage rate is not applicable to individual sellers. It shows what the entire eBay platform is selling, for any given item or listing, as though eBay is one large store. It does not mean that your store will also have the same success.  

Ex. “Walmart sells lots of hammers at X.XX% STR. That means, "If I sell hammers, I’ll sell lots of hammers at the same X.XX% STR.”

The current STR line of thinking assumes that all listings and all products in those listings are equally the same. However, we know not all listings are equal. Some never sell and not all listings sell at the same speed or price. For this reason, the calculated STR figure cannot be assumed to be the same for every seller. It is the STR for the entire eBay marketplace and individual results may vary greatly. 

Need proof? If the calculated STR is applicable to your item, then why is it that every seller will calculate the same STR%? Can every seller have the same STR? No, the reason we all get the same STR% is because it is the STR for eBay and not individual sellers.

This leads us to the second point. What sells on eBay or what another seller on eBay sells, does not impact the probability of your item selling.  

#2: The Gambler's Fallacy as it applies to comping on the eBay app.  

The Gambler's Fallacy refers to the erroneous thinking that a certain event is more or less likely, given a previous series of events. Why is this wrong? 

Because if a series of events is random and the events are independent from one another, then by definition the outcome of one or more events cannot influence or predict the outcome of the next event. 

Here it is renamed the “Reseller’s Fallacy” to refer to a seller’s expectation that a sale from another seller will influence the probability of selling their own product. This is witnessed when a seller assumes either a previous sale or the expected sell thru rate will apply to their own listing for the same or similar item. Why is that assumption incorrect?

Because…buyer decision making and shopping behavior combined with the incalculable number of variations in product quality, listing quality and seller access to eBay; results in the final purchase of any given product being a random event. 

If each sale is a random event, then we cannot base the sale of our item on any previous event.  What we can do is, look at the current market information and make informed decisions about what is going on now.

#3: The effects of Confirmation Bias positively support previous STR beliefs.


“Confirmation bias” is a person’s tendency to process information by looking for, or interpreting, information that is consistent with their existing beliefs. This biased approach to decision making is largely unintentional, and it results in a person ignoring information that is inconsistent with their beliefs. These beliefs can include a person’s expectations in a given situation and their predictions about a particular outcome. People are especially likely to process information to support their own beliefs when an issue is highly important or self-relevant.

How does this apply to sell thru rate? 

Sellers will frequently use calculated STR for comping prior to purchasing. Many of us pride ourselves on running comps and calculating STR. However, few follow up to confirm if that STR was correct when the item sells. 

This is a type of bias where the seller believes so strongly that the estimated STR was correct, that they never follow up to confirm. Or is it a fear of not wanting to ask if it failed? Either way, listings that sit too long tend to bring out different flavors of blame for the eBay marketplace, algorithm, listing patterns, time away, and many many others.


The bias is to confirm the use of STR when an item sells or sells quickly and conversely to ignore the STR if the item is not selling or is very old. Further, the entirety of the reselling universe confirms and supports this bias through discussions, videos, blogs etc. 

The belief in Solds and the eBay app calculated STR is so strong, there isn’t one voice of descent to this very ingrained way of comping. Until now. Give it a try at www.TheReSellerLife.com.


About the Author

Sean Gay is the founder of ReSeller Inc, VERO Heroes and Thank Tink llc. When he's not supporting and developing ReSeller, he geeks out on old dictionaries, inventing new products and playing board games with his family. He calls Richmond, VA home.