Below is an article on the topic of practice method by Noa Kageyama. A good read!
http://www.bulletproofmusician.com/struggling-to-get-a-tricky-passage-up-to-tempo-try-this-clever-practice-technique/
"These results suggest that in the early stages of learning a skill, emphasizing accuracy can absolutely lead to more accurate results in the short term – but this may come at the expense of long-term development. "
"Habits and mechanics that will eventually have to be discarded or unlearned, in favor of more efficient and speed-friendly mechanics which do work at the final tempo."
http://www.bulletproofmusician.com/struggling-to-get-a-tricky-passage-up-to-tempo-try-this-clever-practice-technique/
"These results suggest that in the early stages of learning a skill, emphasizing accuracy can absolutely lead to more accurate results in the short term – but this may come at the expense of long-term development. "
"Habits and mechanics that will eventually have to be discarded or unlearned, in favor of more efficient and speed-friendly mechanics which do work at the final tempo."