I recently read where someone said that GitHub was the place to go to determine a developer's skill level. I have to say that I totally disagree with this statement. It might be true for some developers, but not me.
I write a lot of code every day. Some days it's hundreds of lines (and others it's only one or two, depending on how many times I refactor it). Almost none of that code makes it to my GitHub profile. In fact, the code that does make it to my GitHub profile is mostly throw-away code of side-projects that I work on in my spare time to prove a concept. While I'll do my best to make it good, maintainability and reuse are not on the top of my list when writing this kind of code. I'm usually trying to prove a concept and get an idea out as quickly as possible.
If you were to look at my public repositories on GitHub, you would see code going back a few years. You'd also see code that I haven't touched in as many years. This code most likely sucks. It probably sucked when I wrote it and it's no less sucky today. It should not be used to judge me as a developer.
The important code that I write each day is locked behind a proprietary wall that is not accessible to the public. Most of my proudest moments as a developer happen when I solve a big problem for my employer. My employer owns that code, not me. Sometimes, I'll take what I've learned and apply it to my personal projects and maybe even blog about it, but the code that I write at work stays at work.
If I was a professional developer whose job it was to contribute to an open source project full time, then I would agree that I could be judged by my GitHub contributions, but I don't think most GitHub projects fall into that category.
I even use GitHub to store non code related things like our group Pathfinder character portfolios for Hero Lab.
Please don't judge my abilities as a developer based solely on my GitHub code. I don't think it's a fair assessment. That code isn't living like the code I work on every day at work.