Evidence receipt / belief
Published · transcript-backedRonny Kohavi: belief
27 Jul 2023 Lenny's Podcast The ultimate guide to A/B testing | Ronny Kohavi (Airbnb, Microsoft, Amazon)
“I think one of the mistakes that some company makes is they launch a lot of experiments and never go back and summarize the learnings.”
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Everything needed to verify it.
- Speaker
- Ronny Kohavi
- Attribution
- Verified speaker
- Claim type
- belief
- Recorded
- 27 Jul 2023
- Publisher
- Lenny's Podcast
Transcript context
…I feel like you feed that into ChatGPT, and you have basically a product manager creating a roadmap tool. In general, by the way, a lot of that is institutional memory, which is can you document things well enough so that the organization remembers the successes and failures, and learns from them? I think one of the mistakes that some company makes is they launch a lot of experiments and never go back and summarize the learnings. So I've actually put a lot of effort in this idea of institutional learning, of doing the quarterly meeting of the most surprising experiments. By the way, surprising is another question that people often are not clear about. What is a surprising experiment? To me, a surprising experiment is one where the estimated result beforehand and the actual result differ by a lot. So that absolute value of the difference is large. Now you can expect something to be great and it's flat. Well, you learn something. But if you expect something to be small and it turns out to be great, like that ad title promotion, then you've learned a lot. Or conversely, if you expect that something will be small and it's very negative, you can learn a lot by understanding why this was so negative. And that's interesting. So we focused not just on the winners, but also surprising losers, things that people thought would be a no-brainer to run. And then for some reason, it was very negative. And sometimes, it's that negative that gives you insight. Actually, I'm just coming up with one example that of that, that I should mention. We were running this experiment at Microsoft to improve the windows indexer, and the team was able to show on offline tests that it does much better at indexing, and they showed some relevance is higher, and all these good things. And then they ran it as an experiment. You know what happened? Surprising result. Indexing the relevance was actually high, but it killed a battery life. So here's something that comes from left field that you didn't expect. It was consuming a lot more CPU on laptops. It was killing the laptops. And therefore, okay, we learned something. Let's document it. Let's remember this, so that we now take this other factor into account as we design the next iteration. What advice do you have for people to actually remember these surprises? You said that a lot of it is institutional. What do you recommend people do so that they can actually remember this when people leave, say three years later?…
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