Pop Price Guide Migration: Updating the PPG Estimated Value Algorithm

PPG Migration

As a price guide, pricing is what we do. We always want to ensure that we are doing the best job possible with accurate, up-to-date information that you can’t find anywhere else. As a result, the Pop Price Guide database is already home to more than five million price points.

Despite the growth, we were held back by our previous Estimated Value Algorithm, which was five years old and hard-coded to the old site, making it, for example, unable to use any price point older than 90 days.

On Thursday, we released an updated version of the PPG Estimated Value Algorithm. These updates include the ability to allow price points that were older than 90 days and the proper inclusion of third party prices from other marketplaces (such as hobbyDB). Those older price points that we have now added have a lower weight to ensure that price trends are properly taken into account, for example when an item increases in value over time (to avoid what is called Underfitting).

PPG Migration

As with some of our recent changes, there were some unintended hiccups with this latest release.  This update had a substantial impact on the value of about 1-2 percent of the items in the guide, basically items with the biggest value shifts. For these items, price points older than 90 days were over-weighted and therefore were skewing Estimated Values, mostly to be too low. 

A fix for this is set to be released in the next few days and should correct this issue. We’ll post an update on our social channels as soon as everything looks good to go.

We believe that once this fix is released, we will have a much more accurate algorithm. Let us know if you encounter any possible but rare inaccurate patterns like a an S-Shape (price increased, then decreased and then increased significantly in a short period of time).


Why else is all of this exciting?

We like to build on that old saying about the more data the better, specifically, the more charts the better!  The earlier update allowed us to add the Top Ten Over Time chart in your Showcase and when we have more time to do the same for all of your Collection, all of your Wish List and more.

In case you have not seen yet, this is the new Top 10 Over Time chart in your Showcase


With this update, we are now in a position to do much more fun stuff! Here are mockups of some of these new features we like to bring to you –


PPG Migration

Ability to select different price sources (in this mockup you can compare different price sources, say eBay and hobbyDB as well as exclude price sources. At a glance, it’s easy to see that you should buy on the green market and sell on the blue one!


PPG Migration

Ability to Zoom in what particular price point changed the Estimated Value at any time


PPG Migration

See  your own purchase(s) in context


PPG Migration

The ability to compare against other items or even series

We want to hear from you

As always, we are here to answer any questions or concerns. Reach out to us by clicking the vertical green Contact hobbyDB button located on the right hand side of every page.

28 thoughts on “Pop Price Guide Migration: Updating the PPG Estimated Value Algorithm

  1. This pricing algorithm killed the price of some limited edition items. Trending values should not factor sales from items that were very limited runs as the hobby has really grown. Deadpool Freddy went from 750 to 290 under the new algorithm. Sales have average 750 to 900 hundred for close to a year. This needs some more tweaking.

    1. Yes, it does. Coming most likely as a release tomorrow or Wednesday (which means it is reflected in prices in the 24 hours after that).

  2. The new algorithm has killed prices on any high end pops from a lot of the earlier years and doesn’t reflect current trending prices. Personally any prices more than 90 days old shouldn’t be used.

    1. Hi Michael, for many items prices older than 90 days are the only prices (for example early Wobblers). Please check after the latest fix is applied and let us know if you find items that you think have Estimated Values that don’t correspond to the data (which is all right below it) and we will check. All items that had been flagged over the last 48 hours or so that we tested are good after applying the incremental fix.

  3. I have a question. To avoid shadow bids to affect the value of a Pop, Are you using interval of confidence? Excluding values that are at the limits of the prices for the single Pop, will provide a more accurate price average

    1. Price points get verified by a human using different methods. I am not familiar with interval of confidence (we are familiar with he Confidence Interval as a statistics tool but am not sure how that would apply here). All we are interested in (a) is the item sold in good enough condition and (b) was it paid for in a bona fide transaction, i.e. is it a market price.

  4. How did Planet Arlia Vegeta go from 3200 to 1800 overnight? With algorithms causing errors like this you could single handedly kill the market for grails. Hope you guys dial this in as PPG has been the go to source for buying and selling.

      1. The planet Arlia Vegeta is still much lower than the original $3120 value…. are the updates completed now and this new algorithm is supposed to give the more “accurate” value of the pops now?

        1. Yes, we are done for now but might do smaller changes going forward. There are many different price curves (steady increase, a Bell Shape, event-based changes etc) as well as other important elements (outliers, blips etc) to pricing. I believe we got a much more robust algorithm now, see for yourself


          I think the new Estimated Value corresponds better with the data (it seems that anything from $2,500 to $2,750 could be reasonable argued with $2,550 being slightly conservative protecting the owner as it is leaving more upside than downside.

  5. Holding you guys to get things updated. And avoid the fake sales and all those fake pops sold killed values to older vaulted pops.

    1. Absolutely, if you see any price point (they all show below the chart) that you think is not kosher flag it (the little red flag next to it).

  6. Does an item need to be marked public in order to be viewed in the showcase? Is this also the case for lists? I can not see my lists or any of my items marked private in my showcase.

    1. Yes, for now. Private items and lists do not show in the Showcase for either the owner or others. But we are soon changing that (there is no reason for an owner not to see their items in the Showcase).

  7. Is there anyway you can add a separate column for certain pops that are being replicated or custom. So buyers and sellers can be aware that certain pops are being faked. Not all pops have fakes currently in the market but certain pops can easily be found on ebay which can affect pricing.

  8. There is one seller on Ebay who is running auctions with no minimum bid, selling hard to find pops for $2 and $3 single handedly devaluating hundreds of items.

    1. I corrected that mistake. Price points get added by volunteers and while they are superheroes they are still only human… and thus make mistakes. If you think something is wrong please check the underlying transactions and if there is one wrong flag it (here it was a sale of an item where the box had significant enough damage so that it should have been excluded).

  9. Hello PPG, what are the status now? Should we keep flagging pops if we disagre with the value? or is your algoryth so tuned in it shows the almost correct value now ?

    1. Hi, the algo is fine. Some transactions might be wrongly reported (for example the wrong sticker or an item sold had some damage). We will always have some of those, please report them when you see them!

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