I wonder where they're getting those numbers from, as I didn't spend anywhere near that long preparing o_O If it was rephrased as "successful candidates will have spent an average of 10-15 hours writing code over the past week" (ie, just working your regular day job counts as "preparation", since you're flexing your coding muscles), that sounds more believable...
Read /r/cscareerquestions/ to get an idea of the levels of prep that many candidates go through. Not everyone needs that level of prep - especially if they're interviewing candidates at their current job. (No better way to see how not to fail by seeing endless failures)
People prepping 100+ hours for interviews at these big tech companies is completely common. After all, spending 100 hours to get 100k+ more comp is a pretty good tradeoff. It's just sad when you do all that prep but fail anyway.
It might be a good tradeoff for the individual candidate, but it’s a terrible practice for the hiring company. It’s like hiring a physicist by giving them a pop quiz on quantum electrodynamics.
If what they meant, then they’re not saying anything meaningful. Anyone working full time as a software engineer who isn’t slacking off to an unimaginable extent is spending 10-15 hours writing code in the course of a week.
For software engineering positions I'd expect you're right - for my own role (production engineering) it's a meaningful metric as we're often hiring sysadmins who have used their coding skills to automate themselves out of a job, while filtering out the sysadmins who have only ever used off-the-shelf tools without looking under the hood :)
