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Major Change: Standard for Deciding Why a Ball MovedGolf's New Rules


Golf's New Rules: Major Changes

New Rule: Under Rule 9.2, the “known or virtually certain” standard (meaning at least 95% likely) applies to all questions of fact about why a ball at rest moved:

  • A player, opponent or outside influence is 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 is assumed that natural forces caused it to move.

Reasons for Change:

The weight of the evidence test in the previous Rules was often difficult to apply in ball moved situations:

  • Many competing factors needed 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
  • There was no prescribed way of prioritizing or balancing these factors.


The “known or virtually certain” standard is simpler to apply because it eliminates most “close calls” where it is hard to know for sure why the ball moved.

This Rule change also means that only the single standard of “known or virtually certain” is used for all ball moved questions, rather than the situation under the previous Rules where different standards applied in deciding whether an outside influence moved a ball or whether the player or opponent did so.