Wow, you did spend a lot of time on these exams. 160 hrs a month, 3 months, 2 developers, that's 960 hours, easily. For 100 candidates, that would mean you spent almost 10 hours on average per candidate. In this case, I think you may have been spending more time on many of them than they are spending on you. However I may feel about take home exams in general, I will certainly say that clearly you are not using take-home exams externalize the inefficiencies of the interview process.
Unfortunately, I don't have any much evidence for my next statement, other than bits and pieces, but I think you are not a common case here. I don't think that most companies do anything close to what you're doing with these take home exams. My defense for this statement without much data is that companies are deliberately secretive about this - I understand it is for legal reasons, but I have no idea, none, if anyone even looked at my project.
Remember, McDowell said that this approach allows the company to burn a lot of a candidate's time, but not the other way around", but it doesn't say that they necessarily do. It's just that the equivalence (a 1 hour interview necessarily involves one hour of the company's time) isn't built into the process, it leaves the door for this kind of time wasting and abuse open, and I'm pretty sure lots of companies do abuse it this way.
BTW, if an employer promised to spend 10 hours reviewing my 6-7 hour homework project, with feedback, I'd try to find a way to make the time available, because it would be beneficial to me regardless of whether I got the job. But if they brush me off with a one liner from a recruiter a full month later, and ask people not to post the project to github (even if it might lead to interesting and novel solutions), I'm going to guess that they aren't doing what you're doing with these projects.
Unfortunately, I don't have any much evidence for my next statement, other than bits and pieces, but I think you are not a common case here. I don't think that most companies do anything close to what you're doing with these take home exams. My defense for this statement without much data is that companies are deliberately secretive about this - I understand it is for legal reasons, but I have no idea, none, if anyone even looked at my project.
Remember, McDowell said that this approach allows the company to burn a lot of a candidate's time, but not the other way around", but it doesn't say that they necessarily do. It's just that the equivalence (a 1 hour interview necessarily involves one hour of the company's time) isn't built into the process, it leaves the door for this kind of time wasting and abuse open, and I'm pretty sure lots of companies do abuse it this way.
BTW, if an employer promised to spend 10 hours reviewing my 6-7 hour homework project, with feedback, I'd try to find a way to make the time available, because it would be beneficial to me regardless of whether I got the job. But if they brush me off with a one liner from a recruiter a full month later, and ask people not to post the project to github (even if it might lead to interesting and novel solutions), I'm going to guess that they aren't doing what you're doing with these projects.