Flaws with the eBay Trust model

Ever since eBay’s conception, many have cited it’s user trust model as a cornerstone to it’s success. The theory goes, if someone conducts themselves well on eBay then their trust level will increase. Conversely, if someone behaves inappropriately then it will soon show as their rating is diminished. Buyers and sellers can use this rating to decide whether they want to do business with a given person.

However, I’ve always found it to be a shaky system at best – with a number of potential flaws. Recently I have fallen foul of some of those flaws…

It all started when I purchased two USB mobile phone chargers for a friend who didn’t have an eBay account. I had purchased chargers from this seller (e-cafe) before, and so I was happy to put my rating on the line for the transaction, as I didn’t expect any problems with a repeat purchase.

When the items arrived they were not Sony Ericcson ones as described in the auction, and as I had received previously from a previous auction. To cut a long story short, none of my email were returned by the seller and eventually I used PayPal arbitration to get my money back (they too didn’t get any response from the seller and so I was awarded a full refund by default).

At this point I contacted the seller to explain what I had done and that they could contact me to discuss how I could return the wrong chargers back to them.

As a responsible member of the eBay community, I obviously decided to leave negative feedback for the seller for the two items (two auctions) – to ensure that others were aware of what had happened and to help them decide whether they wanted to do business with the seller.

Today I have discovered that the seller has decided to give me negative feedback too, for both auctions! Pretty cheeky, considering I didn’t do anything wrong!

Some further investigation showed that where I had originally left him negative feedback on his profile, he had responded saying that would be giving me negative feedback in retribution:

bmetcalfe: Wrong item sent. No response to any emails, had to revoke payment via PayPal. 🙁
Reply by e-cafe: Buyers, REMEMBER NEGATIVE GOES BOTH WAYS. NEG 4 BUYER TOO!

Clearly this is simple retribution – he practically says so in his response. “You gave me a negative feedback score, so I will give you one back too”.

Flaw #1: eBay’s trust model doesn’t prevent “tit-for-tat” rating, where one party can hold back giving their rating until they receive theirs. When they do receive their rating, they can decide whether to give back a negative rating in retribution.

Effect: A “culture of fear” can be created where a people don’t want to leave negative feedback for fear of being negatively labelled themselves and thereby souring their own trust rating.

Solution: Hide the rating the other party has given until both parties have submitted their own rating or a set amount of time has passed at which point they loose their option of rating the transaction.

Flaw #2: Proportionality. For an eBayer with a large number of positive transactions who has turned bad, it can take a long time before their rating is sufficiently dented.

To give an example, e-cafe, the other party in my transaction, has a total of 9977 positive comments and 203 negative ones, leaving them with a net score of 9773 or 98%.

Effect: Recently poor performing eBayers who have had a previously good record can trade for a long time before they appear to be less trustworthy (unless other party inspects their feedback history carefully – but this is still useless when trying to use the numerical metric for a programmatic approach). This is particularly crucial when you consider there is a big trade in selling well-trusted eBay accounts.

Solution: Weight feedback based on time or produce more than one metric – one that indicates recent trading history in addition to entire trading history.

Ensure overship of eBay accounts cannot be transferred, although this is admittedly difficult as they can be attached to a free email address – the ownership of which could easily be changed too

Flaw #3: Ratings don’t represent the “value” of the transaction. It turns out that the auctions that I got a “bad mark from” were worth just 80p (+ P&P).

Effect: Looking at my feedback history now looks like I am untrustworthy eBayer despite the fact that I have received positive feedback on auctions for items costing £1000’s.

Solution: Weight ratings based on transaction value. This has the effect that a high-value auction that has gone well will cancel out more than one low-value auctions that have not gone so well or been wrongly/spitefully graded (as discussed above).

I think this model is representative of real life. It takes a lot less trust to feel happy buying a CD or a book from someone than it does to buy a car from them. Or to put it a different way, once I’d bought a high-value item like a car from someone, I’d feel a lot more confident of their trustworthyness than if I had bought three or four low-value items from them – such as books.

My final frustration with the eBay Trust mechanism is eBay’s reluctance to get involved with any disputes. There appear to be no ways one can appeal against a feedback score. In real life, if someone claims you were untrustworthy there are steps one can take to appeal against that claim. On eBay there are none.