Online reviews are a public good and increase social welfare, but they could be improved by including more concrete data. For example, a restaurant or grocery store review should list the prices of specific foods. A review of a bar or function venue could estimate the number of tables and seats and the distance between tables, thus quantifying how cramped the room is. Currently, most reviews on Google Maps, Yelp and other similar sites are vague, just stating that the reviewer had a bad or great experience, that the staff were helpful or not, etc.
The purpose of a review is (hopefully) to help others (although some people just write rants to vent their emotions). Facts in reviews would help others more than opinions. Photos of the establishment and the food are useful, because they provide factual information. Some photos are more helpful than others. For example, it is more useful to see the inside than the outside of a venue. It is not very useful to see a picture of the outdoor sign of the establishment, but a readable photo of the menu conveys lots of information. In the future, Google Maps and competitors could automatically extract text from photos that contain it, and display the information in search results. Then photos of the menu, or of prices in a grocery store would be even more useful.
The idea for this post came from fruitlessly searching the web for current prices of groceries in different supermarkets in town. It would have been helpful if recent reviews of these supermarkets had included prices of at least some items.
The grocery price comparison apps that I tried had the limitation that the prices were for specific branded products and per package (e.g. Organic Carrots 500g), not per kilogram of a generic product (e.g. 1kg of carrots). This made it difficult to compare general pricing across shops, because each shop has a different range of brands, and only the price of the exact same brand can be compared.
An easy fix to improve the apps would be to allow users to specify which differently-branded products should be treated as identical, for example “Coles orange juice 2 litres” is the same for me as “Woolworths orange juice 2 litres”. Merging similar products would also reduce the memory requirement of the app, because the product database would have fewer entries to keep track of.
I do like the price comparison app idea. Although at this point one might as well go full ‘lab experiment’ on app users and allow them to indicate the price differential at which they would be indifferent, i.e. “if X is $1 (or 20%) more expensive than Y then they are the same to me”. This would also allow for comparison between containers of different sizes within the same product — e.g., 1L milk bottle is worth to me about as much as 2L or 1gal milk bottles because I don’t consume that much milk, but this is definitely not the case for many other consumers.
Trivially, such option would (given a decent userbase) create a nifty dataset demonstrating the whole spectrum of violations of transitivity.
Agreed that the user-submitted preferences are a good research dataset. Another useful application would be to recommend similar products to other users, e.g. “most people considered these two products equivalent”. So if someone searches for a generic product like peanut butter, then the prices of all similar peanut butters in surrounding shops would come up, not just the price for one particular store’s one brand.