Why Doesn't Amazon's Price Sort Work?

Sorting by price is hard - if you really wanted to do a true price sort you end up with the long tail of products that match the term "ipod" (but are very loosely related to ipods) at the top of search results. Try searching for ipod in electronics and sorting by price.:

http://www.amazon.com/gp/search/ref=sr_nr_i_0?rh=k%3Aipod%2C...

I get a usb connector, stereo speaker, some other mp3 players, etc. all among the top 6 results. Only 2 ipods on the first page. At least there is a link to a department containing just the ipods.

So in order to avoid doing really badly you don't allow searching by pure price, but rather use a combination of price and relevancy (and this can only take you so far as the results above demonstrate.)

There's a search filter option to select "Prime eligible" items, but when you select it, the price sorting still seems to include Marketplace vendors. Selecting the "New" search filter does not help.

There's even a search filter for "Seller" that allows you to select only amazon.com, but the price sort is still wrong if this is selected!

(I understand that Amazon probably prefers that we stumble upon the marketplace vendors, but it's frustrating when you can't disable it even temporarily.)

I often find myself doing product filtering on other sites (yes, I feel a bit bad about this) and then (usually) buying on Amazon because of price and the free Prime shipping.

eg. I'll figure out what I want to buy for a new computer system on Newegg, because their combined browse-search is way better than Amazon's, and then take the final result and see if it is worth buying on Amazon via a direct parts name/number search. Amazon loses about 10-20% of the sales I would have otherwise just given them due to this when it turns out the cost to buy the item on the other site I was using is similar enough to the Amazon price. When the price is even close I favor the other site since they provided me a better UX experience, but I do admit that if the overall cost to buy on Amazon is significantly cheaper, I'll still buy from them.

Broken price sort is a common complaint both inside and outside of Amazon. There have been email threads, tickets, and half working solutions to this but nothing -- so far -- has worked well enough.

First of all, no engineer at Amazon would tell you that the current state of price sort is acceptable. It is a well known problem that gets worked on from time to time (In fact, better price sort was going to be my next project before I left so, uh, sorry Internet...). The current price sort has been around for a long time and nothing has outperformed it.

Amazon can't sort by price well for several reasons.

1. What do you mean by price?

2. Low cost accessories

3. Bad item classification

4. More things that I can't get into

1. Price is hard to figure out. Do you want to sort by the base price of an item, the price plus shipping (which depends on where you live), or the price after discounts or specials? What about products that are sold both by Amazon and third party sellers, where the 3p seller charges less for the item but more for shipping than Amazon? Which price should be shown?

2. Low cost accessories dominate searches for a product. If you search for "iPod" in all-products search (APS, the default search on the front page) then you get pretty relevant results that span a few categories. To sort those you first need to select a category (we'll get to that later) and then sort by price. If you select electronics you'll see a few relevant results and a ton of accessories.

You could argue that Amazon should have better algorithms (and that's probably true), but there's only so much you can do. If you really want to sort by price then you shouldn't care about the relevancy of the results. To argue otherwise means that you won't have results that are increasing in price as you scroll down. You'll see more relevant but more expensive results at the front.

3. Both 3p and internal item-to-category classification continues to be a struggle at Amazon. I knew several people on the team that helped improve item classification while I was there and they did great work and made huge improvements to the catalog accuracy. Amazon has systems that learn the correct classification and suggest the correct categories to 3p sellers. Unfortunately, you'll still find sofas in the electronics category. This really screws up the results. Your outs are only as good as your ins.

4. There are some fundamental design choices that make solving this issue really hard. I obviously can't go into such fine detail, but try to appreciate that really smart people are working really hard so you can buy the lowest priced product as easily as possible.

In direct response to the article:

> Why would Amazon fail badly at something that seems so simple? The immediate cause is probably caching. Amazon likely has a task that periodically caches the low price for each item.

Well, caching is used extensively, but this probably isn't why the results look like they do. See #1.

> Tellingly, if you search for items without many Marketplace listings, the price sort is much more reliable.

Again, that's because if you exclude marketplace sellers the price is easier to calculate.

> Perhaps they can stop trying; why not just exclude Marketplace items from the price sort calculation altogether?

Seriously? Exclude a huge portion of all the products sold on Amazon? Crazy.

Price sort is hard. Just sort by popularity.

It's the easiest problem to solve. Just remove bad categorization.

Open Amazon, click any category. Let's say hdmi cables. What do you see? Probably televisions, screws, microwave ovens, inflatable sex dolls, anything!

They let bad Sellers fill their categories with crap. Now you can't search.

And that's some kind of difficult problem to solve? Give me a break.