  Traditional assessments of tackling in American Football often only consider
the number of tackles made, without adequately accounting for their context and
importance for the game. Aiming for improvement, we develop a metric that
quantifies the value of a tackle in terms of the prevented expected points
(PEP). Specifically, we compare the real end-of-play yard line of tackles with
the predicted yard line given the hypothetical situation that the tackle had
been missed. For this, we use high-resolution tracking data, that capture the
position and velocity of players, and a random forest to account for
uncertainty and multi-modality in yard-line prediction. Moreover, we
acknowledge the difference in the importance of tackles by assigning an
expected points value to each individual tree prediction of the random forest.
Finally, to relate the value of tackles to a player's ability to tackle, we fit
a suitable mixed-effect model to the PEP values. Our approach contributes to a
deeper understanding of defensive performances in American football and offers
valuable insights for coaches and analysts.
