Measures & metrics of "grit" are, at best, not that great. It is a quality difficult to capture, and methods tend not to distinguish between projects a person chooses to undertake and those a person has no interest, believes are without value, yet is forced to undertake. I've used Duckworth's grit assessments, and not found the results to be particularly predictive of the outcomes I was trying to measure
Now, that said, "grit" is not always well understood. It's often considered a general-purpose quality. However, grit isn't necessarily about being good, or "gritty", at everything. It's much more about how you perform on something once you've chosen to do that thing. It is not about doing things that you don't believe have value to yourself.
The athlete that sleeps through class is a good example: That person didn't explicitly choose academics. Academic responsibilities were an unwanted side effect. It wasn't something the person ever really wanted.
Compare that with someone who chooses to go to college for academic reasons: Do they work hard? Stick to it? Persevere through problems? That is grit.
Now, that said, "grit" is not always well understood. It's often considered a general-purpose quality. However, grit isn't necessarily about being good, or "gritty", at everything. It's much more about how you perform on something once you've chosen to do that thing. It is not about doing things that you don't believe have value to yourself.
The athlete that sleeps through class is a good example: That person didn't explicitly choose academics. Academic responsibilities were an unwanted side effect. It wasn't something the person ever really wanted.
Compare that with someone who chooses to go to college for academic reasons: Do they work hard? Stick to it? Persevere through problems? That is grit.