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CORE Brown Bag Seminar
By Brown Bag Seminar

Jui Pin Robin Ng


will give a presentation on

Ratings and Reciprocity


The study of review systems has gained prominence with marketplaces, such as eBay, Airbnb and Amazon, and social media platforms, such as Facebook and Twitter. Today, there are marketplaces which focus purely on the provision of reviews, such as Google reviews, Yelp and TripAdvisor. The growing empirical evidence puts into question the exact usefulness of reviews, suggesting that ratings may be overinflated. New evidence also suggests that the provision of reviews are intrinsically motivated - by kindness towards sellers and other buyers. We develop what we consider to be the first theoretical model that attempts to explain the inflation phenomenon by incorporating kindness into a model for ratings. We find that there are multiple channels for ratings inflation and while ratings inflation may necessarily diminish the informativeness of ratings, it may not necessarily cause a reduction in consumer surplus.

To join the seminar, please follow the following instructions:

1. Indicate on Doodle by Tuesday 24th of November at 12:00, using your full name, whether you will be joining the conference (

2. If you are not a member of the CORE BrownBag team on Microsoft Teams, please click here ( or write us an email.

3. The interface of Teams is very similar to Skype. When the presenter starts the videoconference, you will see in the team page the button "join". Just press it and you will be inside the video conference.

4. By the start of the seminar, you should mute your microphone. This should be done to avoid echoing noise problems. Whenever you want to intervene, please raise your hand or write in the chat that you want to do so. The presenter will stop, you can unmute yourself and intervene.

25 November
12:50 - 13:50
This is an online event at CO35 and by Teams Go to event website