Definition: The CPD tracks the running difference between the total points won by Player 1 and Player 2 at any given moment in the match.

Formula: $$CPD_t = (P1_Points_Won_t) - (P2_Points_Won_t)$$

Interpretation:

CPD > 0: Player 1 is currently performing better (leading in total points).
CPD < 0: Player 2 is currently performing better (leading in total points).
CPD = 0: The match is tied in terms of points won.
Contextual Adjustment (Serving): Since the server has a higher probability of winning, the 'flow' is most significant when the CPD trends upwards during the opponent's service games (break points) or maintains stability during one's own service games. The visualization will plot CPD over time (point number) to show the momentum shifts.