I'm still not sure how giving employees a book to read and then testing them on it is a good process. If I'm going to spend a couple months of free time learning something, I'd pick something like Python or Android development or HTML5 app development, rather than learning a skill that will only be useful for 1-3 employers.
How can I know if an employer is worth 1-3 months of my free time until I meet my potential future coworkers? Demanding a candidate invest 1-3 months of free time before you meet them seems like an insult to me.
If your job uses a niche skill, why demand candidates be an expert already before you hire them?
I did not have a problem with passing on candidates who weren't not sold on learning our subspecialty.
I do have a problem with passing on candidates who were sold on our subspecialty, had an aptitude for it, but could not pass an interview on it "cold".
To me, that sounds like a convincing argument that your specialty is not worth learning. I'd rather work someplace that wants to invest in their employees, rather than expecting them to already be experts in some obscure techniques.
Are you hiring people who are brilliant, or people who are so desperate that they'll spend a couple months preparing for one interview?
Let's not flee to abstraction. Matasano/NCC does software security. We were willing to invest some time and money to bring people up to speed in software security and exploit development.
Not your cup of tea? Totally fine. Not everyone is interested in doing security.
How can I know if an employer is worth 1-3 months of my free time until I meet my potential future coworkers? Demanding a candidate invest 1-3 months of free time before you meet them seems like an insult to me.
If your job uses a niche skill, why demand candidates be an expert already before you hire them?