Just in case you haven't seen this TED talk from 2013 it's worth a watch. Working with students every day I've seen first hand that this is true. Attitude is everything and perseverance is vital for classroom and life success.
If you want to take the Grit Scale test and see further research and Angela's book click here.
Another recent article citing Carol Dweck's work on attitude being more important than intelligence is here.
"Leaving a high-flying job in consulting, Angela Lee Duckworth took a job teaching math to seventh graders in a New York public school. She quickly realized that IQ wasn't the only thing separating the successful students from those who struggled. Here, she explains her theory of "grit" as a predictor of success."