Reward-based training is both more effective and less harmful to dog welfare than punishment-based methods.
Dogs subjected to aversive training methods — shock collars, choke chains, alpha rolls — experience fear and pain that constitutes genuine welfare harm. Beyond the individual harm, punishment-based training damages the human-dog relationship, increases anxiety, and often increases the very behaviours it aims to suppress. There is no welfare or efficacy justification for aversive training when positive alternatives achieve better outcomes.