The 1.5 or one-and-a-half method is an advanced strategy that's mainly used to increase time under tension to stimulate hypertrophy (muscle growth). But when used with the back squat, it can also be an effective corrective exercise for those who struggle in the bottom position.
Common technical flaws seen in the bottom position of the back squat include:
The inability to hit full depth will limit your ability to maximize strength gains and build muscle mass in the long run. Bodyweight shifting too far forward will result in improper squat mechanics and limit the weight you can lift.
The 1.5 method can fix those problems. Why? Because even with just 2 reps per set you practice the bottom position 4 times.
In addition, in order to rise out of the bottom halfway up and return into the bottom, you need to have a strong and stable bottom squat position.
Give it a shot. You'll improve your technique and build bigger, stronger legs.