Current Rule: The “weight of evidence” standard is used to decide whether a player (or an opponent) caused the player’s ball to move:
Ø The decision must be made in the light of all relevant circumstances, evaluating the weight of the evidence and the balance of probabilities (Decision 34-3/9).
Ø The player will be found to have caused the ball to move if the weight of the evidence indicates that it is more likely than not that he or she was the cause (Decision 18-2/0.5).
But a higher standard (“known or virtually certain”) applies in deciding whether an outside agency (such as an animal, spectator or another player in stroke play) caused a ball to move.
Proposed Rule: Under new Rule 9.2, the “known or virtually certain” standard (meaning at least 95% likely) would apply to all questions of fact about why a ball at rest moved:
Ø A player, opponent or outside influence would be found to have caused the ball to move if the player, opponent or outside influence was known or virtually certain to have caused it to move; otherwise it would be assumed that natural forces caused it to move.
Reasons for Change:
Ø The weight of the evidence test is often difficult to apply in ball moved situations:
o Many competing factors need to be balanced, such as what the player did near the ball, the lapse of time before the ball moved, the lie of the ball, the slope and other course conditions near the ball and the presence of wind or weather conditions, and
o There is no prescribed way of prioritising or balancing these factors.
Ø The “known or virtually certain” standard would be simpler to apply because it would eliminate most “close calls” where it is hard to know for sure why the ball moved.
Ø Using this standard would fit well with the new Rule 13.2 that would eliminate the penalty for accidentally causing a ball to move on the putting green:
o The primary reason for eliminating that penalty is that it is often particularly difficult to decide why a ball moved on the putting green.
o This is explained further in Explanation for Proposed Rule Change - When to Replace Ball that Moves on Putting Green.
o Given those particular difficulties, using the “known or virtually certain” standard would be more clear-cut and easier to apply, and help avoid the risk of players being penalised for playing from a wrong place (replacing the ball when it should have been played as it lies, or vice versa) based on the same difficult balancing of factors that led to eliminating the penalty for causing the ball to move.
Ø This Rule change also means that only the single standard of “known or virtually certain” would be used for all ball moved questions, rather than the situation under the current Rules where different standards apply in deciding whether an outside influence moved a ball or whether the player or opponent did so.