> ...don't have a a vested interest in trying to mislead you. I witnessed this. I briefly worked on the recommendations team for a fashion retailer, doing yeo

> ...don't have a a vested interest in trying to mislead you. I witnessed this. I briefly worked on the recommendations team for a fashion retailer, doing yeoman plumbing and maintenance. Basically an in-house equiv of RichRelevance.com. So, so much data and logging. Alas, after cutting out all the obfuscation layers and steps, the "lift" attributed to the team's exquisite algos proved illusory. Some >80% of the conversions came from the "recently viewed" rule. Whereas the conversation attributed to the algos consuming most of our dev and compute resources was basically noise. I wouldn't say our (very smart) data scientists were fooling themselves, necessarily. More like the feedback loops were never fully validated. (Familiar story of non-programmer domain experts hoisting a POC, which then was promoted to production. Maintenance hell.) Coincidentally, FWIW, my bro has worked in ad tech (Avenue A/Microsoft, RichRelevance, others?). He's got a math skillset. Was a true believer. It took a long time, but he eventually lost his "faith" that digital advertising (as they were doing it) was effective, on the balance. Also FWIW, during my brief stint, I advocated "personalization". What I imagine StitchFix is doing. I'd love to know, for real, how they're doing. Like the split between algos and human "style consultants".