How do Steam Guide ratings and upvotes actually work?

[Tsuey]

Really I'm just curious...

I know that guides need 25 ratings to receive a star, and this guide has exactly 25 ratings:

https://steamcommunity.com/sharedfiles/filedetails/?id=1718035097

However, if the guide is linked in a Steam Chat, it's shown as having 26 upvotes.

How can a guide be 3/5 stars when it has 25 ratings, and 26 upvotes?

Furthermore, as displayed here:

https://steamcommunity.com/app/550/guides/

It is shown to have 4/5 stars -- as if Valve's page-caching is just off right now.

I'm sure all this makes sense somehow -- but... how ?!

Thanks for any insight.

[Tsuey]

I'm sort of answering the question myself for anyone else curious:

https://steamcommunity.com/groups/NewSteamCommunityBeta/discussions/3/828925849481042441/

From Valve's TomB in 2013:

It uses a Bayesian rating system, so that's expected.

The rating system doesn't quite work like that, since the Bayesian formula applied to the ratings dampens the results a bit. That's so the first 10 or 20 or even 30 votes on any given item doesn't make or break it. We require "enough" votes to push an item up or down from the average rating, since we are basically saying that we don't have "enough" information to make a call one way or the other on the quality of the item.

There are quite a few sites with more in-depth information on Bayesian rating systems if you'd like to learn more.

It's a trade-off. Choosing 10 to start showing ratings was deemed most appropriate, since not every item is going to have a ton of ratings and we didn't want the pages littered with "not enough rating" grey stars.

So, whenever a guide reaches its new required minimum of 25 ratings, it's automatically and forcefully shown as 3/5 stars. I presume Valve might also be taking into consideration that people viewing your guide aren't all going to find it useful, and a high volume of people who don't rate coupled with a low volume of people who are very likely to rate it favorably brings the overall star rating down.

https://en.wikipedia.org/wiki/Bayesian_average

Instinctively, it's just strange to see a guide with 26 upvotes and "supposedly" 25 ratings, 26/25 who rated positively but only 3/5 star rating. But taking the Bayesian rating system into account it at least makes... some... sense.

In terms of the initial guide linked, it's either going to appeal or not -- most people indeed open, look, see it's over-complicated, close... those who go about trying it are the ones who are going to rate, and see that it works, hence being favorable.

[Tsuey]

However, it does seem like there's 2 rating systems occurring beside one another, as the L4D2 Guides listing exposes it as 4/5 stars -- but the guide itself says 3/5... as if they're running off different formulas.

Given that it has been this way several hours it doesn't feel like Valve page-caching.

This could be the discovery of a very mild / negligible bug.