Backswing :

 Look at the above picture. It has been taken from behind the student. Notice where the club is in relation to the line of the target after the first centimetres of the swing.

Now here is the same picture with the annotations of the software. We see clearly that the club trajectory is outside the line of the target.  This can cause in the majority of cases an Outside/Inside swing which results in a "slice" or a missed shot.

 Now, here is the picture after the correction of the swing. We see that the club follows the ground accordingly with the line of origin of the swing.