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As someone that used to work on recommendations systems ... the problem is that the signal is just so robust. Stuff other people like really is one of the stron

As someone that used to work on recommendations systems ... the problem is that the signal is just so robust. Stuff other people like really is one of the stronger ways to predict what you will like. Most additional data sources that allow us to customize further and identify what sub-groups you might belong to and thus prioritize highlighting things of relevance to your subgroups tend to empirically show lower performance for the overall population. The only thing I've seen work is focus on the "most popular" things for the most important demographics (such as those with money to buy things) which might overfit for that demo, and underperform overall, but still performs the best on some higher metric like revenue. I commented a while back on someone asking "Why recommend me a ladder if I just bought a ladder, couldn't the system understand that people usually only buy one ladder?" But the fact is, the commenter was wrong about his priors. Actually someone who buys a ladder is indeed more likely to buy another one ... even if most people that buy ladders only buy a single ladder. The fact that you bought a ladder, puts you in the cohort of people that buys ladders, which means you are more likely to buy another one than someone who isn't on the record buying a ladder.

techbio 6y ago
I'm sure the poster you're replying to knows this and wishes it weren't so.
codetrotter 6y ago
> But the fact is, the commenter was wrong about his priors. Actually someone who buys a ladder is indeed more likely to buy another one ... even if most people that buy ladders only buy a single ladder. The fact that you bought a ladder, puts you in the cohort of people that buys ladders, which means you are more likely to buy another one than someone who isn't on the record buying a ladder. Be that as it may it’s still ridiculous. There are very many other things I am going to buy before I buy another ladder. And Amazon should be able to know that because of having seen me search for very many other things in the past that I have not yet bought. And if nothing else, couldn’t they let me at least click a little button next to any suggestions to tell their algorithm that no I am not interested in this recommendation?
wombatmobile 6y ago
> the problem is that the signal is just so robust. That's why you aren't seeing the better solution. You're only seeing what you know, which is the (tired old) signal you know how to detect. But you already detected it, and monetised it. A better recommendation signal would be the one that you don't know how to detect. It's the signal people get unexpectedly from other people, when they chat about the thing they just bought. Call it the n+1 recommendation signal. > The fact that you bought a ladder, puts you in the cohort of people that buys ladders, which means you are more likely to buy another one than someone who isn't on the record buying a ladder. OK, but that's still the n recommendation signal, which has already been monetised, and won't be refreshed for quite some time, in the same way a Venus fly trap takes time before it will open and trigger again. What can a person do with a ladder that she couldn't do before? That question is what begets the n+1 recommendation signal. It isn't a question that even gets asked explicitly. It happens through association. She says "I got a new ladder, and a paintbrush and some paint." and her friend says, "Oh great, I just used my ladder to hang a bird feeder from the sycamore tree!" and then she says "Oh! I've got a sycamore tree too! Where'd you get your bird feeder?"

techbio 6y ago

I'm sure the poster you're replying to knows this and wishes it weren't so.

codetrotter 6y ago

> But the fact is, the commenter was wrong about his priors. Actually someone who buys a ladder is indeed more likely to buy another one ... even if most people that buy ladders only buy a single ladder. The fact that you bought a ladder, puts you in the cohort of people that buys ladders, which means you are more likely to buy another one than someone who isn't on the record buying a ladder. Be that as it may it’s still ridiculous. There are very many other things I am going to buy before I buy another ladder. And Amazon should be able to know that because of having seen me search for very many other things in the past that I have not yet bought. And if nothing else, couldn’t they let me at least click a little button next to any suggestions to tell their algorithm that no I am not interested in this recommendation?

wombatmobile 6y ago

> the problem is that the signal is just so robust. That's why you aren't seeing the better solution. You're only seeing what you know, which is the (tired old) signal you know how to detect. But you already detected it, and monetised it. A better recommendation signal would be the one that you don't know how to detect. It's the signal people get unexpectedly from other people, when they chat about the thing they just bought. Call it the n+1 recommendation signal. > The fact that you bought a ladder, puts you in the cohort of people that buys ladders, which means you are more likely to buy another one than someone who isn't on the record buying a ladder. OK, but that's still the n recommendation signal, which has already been monetised, and won't be refreshed for quite some time, in the same way a Venus fly trap takes time before it will open and trigger again. What can a person do with a ladder that she couldn't do before? That question is what begets the n+1 recommendation signal. It isn't a question that even gets asked explicitly. It happens through association. She says "I got a new ladder, and a paintbrush and some paint." and her friend says, "Oh great, I just used my ladder to hang a bird feeder from the sycamore tree!" and then she says "Oh! I've got a sycamore tree too! Where'd you get your bird feeder?"