I am always telling my students to use slow, concentrated practice to improve accuracy. I'm a fan of slow practice, generally, so I liked the following perspective:
Melanie Spanswick on Slow Practicing http://melaniespanswick.com/2013/10/01/in-praise-of-slow-practice/
"....The first obstacle to successful slow practice is encouraging students and young pianists to view it as a valuable process. Many think it is a good idea in theory, but when it comes to practice time, it’s far easier (and more pleasant too) to play as usual; up to speed with the usual hesitations or errors. It takes vast amounts of discipline to play at a fraction of the speed, which is no easy feat, but once a student is able to see the value, they will generally work at it. All pianists can gain by practising slowly whatever level or standard, including professionals.Slow practice can help with so many different aspects; establishing correct fingering (particularly of rapid passagework), understanding chord structure, promoting suitable hand positions, wrist/arm movement, articulation, dynamic range, phrasing, and just good old note accuracy too! It can help a pianist to grasp the complete picture or structure of a work and gives the brain more time to assimilate every corner or angle of a piece. Whereas playing up to speed often exacerbates ‘hesitations’ or rhythmic/note errors, stumbles and rushing, slow playing gives the feeling of space, time, serenity, clarity and precision. I have written many times about the value of practising separate hands, especially the left alone, and this can be taken one step further by practising separately AND slowly. Slow practice and preparation also really helps a pianist when they want to memorise a piece.
One further aspect that may be alleviated with careful, slow work is tension. Many of us feel tense and stiff whilst playing fast most notably if we haven’t prepared passagework or tricky, demanding sections very well, but if we take time and learn slowly, our upper body will simultaneously relax allowing for free movement and better sound quality. Once accustomed to the motility of playing certain passagework slowly, playing up to speed won’t be an issue because your brain will have already assimilated all necessary movements so speed is literally just a matter of thinking slightly faster. This is crucial if you are working on a piece with leaps or large chordal passages where a loose, free wrist and arm is imperative to the success of the performance......"
Melanie Spanswick on Slow Practicing http://melaniespanswick.com/2013/10/01/in-praise-of-slow-practice/
"....The first obstacle to successful slow practice is encouraging students and young pianists to view it as a valuable process. Many think it is a good idea in theory, but when it comes to practice time, it’s far easier (and more pleasant too) to play as usual; up to speed with the usual hesitations or errors. It takes vast amounts of discipline to play at a fraction of the speed, which is no easy feat, but once a student is able to see the value, they will generally work at it. All pianists can gain by practising slowly whatever level or standard, including professionals.Slow practice can help with so many different aspects; establishing correct fingering (particularly of rapid passagework), understanding chord structure, promoting suitable hand positions, wrist/arm movement, articulation, dynamic range, phrasing, and just good old note accuracy too! It can help a pianist to grasp the complete picture or structure of a work and gives the brain more time to assimilate every corner or angle of a piece. Whereas playing up to speed often exacerbates ‘hesitations’ or rhythmic/note errors, stumbles and rushing, slow playing gives the feeling of space, time, serenity, clarity and precision. I have written many times about the value of practising separate hands, especially the left alone, and this can be taken one step further by practising separately AND slowly. Slow practice and preparation also really helps a pianist when they want to memorise a piece.
One further aspect that may be alleviated with careful, slow work is tension. Many of us feel tense and stiff whilst playing fast most notably if we haven’t prepared passagework or tricky, demanding sections very well, but if we take time and learn slowly, our upper body will simultaneously relax allowing for free movement and better sound quality. Once accustomed to the motility of playing certain passagework slowly, playing up to speed won’t be an issue because your brain will have already assimilated all necessary movements so speed is literally just a matter of thinking slightly faster. This is crucial if you are working on a piece with leaps or large chordal passages where a loose, free wrist and arm is imperative to the success of the performance......"