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Every post on HN with this question receives the same response: “it’s because Amazon knows you’re actually more likely to buy another one if you’ve just bought

by p49k 6y ago

Every post on HN with this question receives the same response: “it’s because Amazon knows you’re actually more likely to buy another one if you’ve just bought one, even if it’s the kind of thing you only need one of (e.g vacuum)” I find that answer unconvincing and there is no published data to back it up, but it is repeated constantly here.

Pokepokalypse 6y ago
Most consumers, in their individual experience, probably avoid foolish purchases like; buying a second widget immediately after buying a first widget. But it's probably true that there are a lot of individuals out there who have done this (for whatever reason), and it's the statistical likelihood of people buying a second widget that drives this. An individual who doesn't do this, can't perceive this "fact" of statistics, which is human behavior in-aggregate form. Individuals only perceive individual behavior.
- _dps 6y ago
  Also, the same-product-again recommendation doesn't have to be a great one; it only has to beat the alternative it displaces. So I could find it plausible that taking a swing on you buying another of a product you already bought beats out whatever the 5th-best recommendation happens to be. Given how widely this policy is criticized, Amazon must be very aware of it and they must continue to do it intentionally. I would trust, given the amount of money on the line, that they see evidence that tells them it's a reasonable choice.
notahacker 6y ago
What they're actually tracking tends to be the fact you've searched for $productcategory (whether you bought or not) In theory since they also have purchase data their 'purchasing intent' categories could exclude people who have subsequently purchased from $productcategory for products which are substitutes (but definitely not products which are complements/consumables/collectibles etc, because someone who has just bought guitar/fishing accessories isn't just likely to buy more guitar/fishing accessories again in future but a lot more likely to than the average person), and yes they could even make guesses about whether somebody is likely to want more than one office chair based on whether they're purchasing as a business or an individual. But in practice it's not easy when they've got a product inventory that's so enormous, complex and dubiously-labelled even the basic product search doesn't work that well, and most of the time the vendors are paying them to show the ads anyway. And still wouldn't be perfect (ironically I seriously considered buying two different vacuum cleaners for different use cases this week!) It's surprising how bad basic targeting is, like when Facebook allowed ad targeting by sexual orientation but even dating websites spent vast sums without bothering, so its unsurprising subtle distinctions about which buyer types only need one of which office accessory are often missed.
spunker540 6y ago
Here’s a different take: when you set up an ad campaign for retargeting, you likely select users who “viewed or added to cart in the last 30 days”; you should also add an exclude for “users who purchased within the last 30 days” but it is very easy to forget the exclusion. Also sometimes there may be communication lags between retailers and ad networks. Some retailers may only upload purchase data daily, sometimes there are gaps in uploads etc. I think most advertisers would prefer to not advertise the same item that people just bought, but it takes perfect execution both technically and from the marketers creating campaigns to pull it off cleanly. When you’re managing dozens of campaigns across half a dozen ad platforms, it’s easy to miss some of the details that matter. And while the wasted ad impressions may annoy the consumers on HN, it is likely a rounding error for advertisers and not a huge cost driver.
- p49k 6y ago
  The most common case of this (as expressed in HN comments over the years) is Amazon recommending products based on Amazon purchase history. In that case it's all first-party data.

by p49k 6y ago

Pokepokalypse 6y ago

Most consumers, in their individual experience, probably avoid foolish purchases like; buying a second widget immediately after buying a first widget. But it's probably true that there are a lot of individuals out there who have done this (for whatever reason), and it's the statistical likelihood of people buying a second widget that drives this. An individual who doesn't do this, can't perceive this "fact" of statistics, which is human behavior in-aggregate form. Individuals only perceive individual behavior.

_dps 6y ago
Also, the same-product-again recommendation doesn't have to be a great one; it only has to beat the alternative it displaces. So I could find it plausible that taking a swing on you buying another of a product you already bought beats out whatever the 5th-best recommendation happens to be. Given how widely this policy is criticized, Amazon must be very aware of it and they must continue to do it intentionally. I would trust, given the amount of money on the line, that they see evidence that tells them it's a reasonable choice.

notahacker 6y ago

What they're actually tracking tends to be the fact you've searched for $productcategory (whether you bought or not) In theory since they also have purchase data their 'purchasing intent' categories could exclude people who have subsequently purchased from $productcategory for products which are substitutes (but definitely not products which are complements/consumables/collectibles etc, because someone who has just bought guitar/fishing accessories isn't just likely to buy more guitar/fishing accessories again in future but a lot more likely to than the average person), and yes they could even make guesses about whether somebody is likely to want more than one office chair based on whether they're purchasing as a business or an individual. But in practice it's not easy when they've got a product inventory that's so enormous, complex and dubiously-labelled even the basic product search doesn't work that well, and most of the time the vendors are paying them to show the ads anyway. And still wouldn't be perfect (ironically I seriously considered buying two different vacuum cleaners for different use cases this week!) It's surprising how bad basic targeting is, like when Facebook allowed ad targeting by sexual orientation but even dating websites spent vast sums without bothering, so its unsurprising subtle distinctions about which buyer types only need one of which office accessory are often missed.

spunker540 6y ago

Here’s a different take: when you set up an ad campaign for retargeting, you likely select users who “viewed or added to cart in the last 30 days”; you should also add an exclude for “users who purchased within the last 30 days” but it is very easy to forget the exclusion. Also sometimes there may be communication lags between retailers and ad networks. Some retailers may only upload purchase data daily, sometimes there are gaps in uploads etc. I think most advertisers would prefer to not advertise the same item that people just bought, but it takes perfect execution both technically and from the marketers creating campaigns to pull it off cleanly. When you’re managing dozens of campaigns across half a dozen ad platforms, it’s easy to miss some of the details that matter. And while the wasted ad impressions may annoy the consumers on HN, it is likely a rounding error for advertisers and not a huge cost driver.

p49k 6y ago
The most common case of this (as expressed in HN comments over the years) is Amazon recommending products based on Amazon purchase history. In that case it's all first-party data.