Casual golfers who like to play their rounds solo will find maintaining a handicap much more restrictive in 2016.

The USGA announced Monday six rules changes to its handicapping system that will go into effect starting Jan. 1, 2016. Most of the revisions are pretty innocuous.

The one that stands out is the note on golfers playing alone. In the change, the USGA states that starting on Jan. 1, 2016, rounds played as a single cannot be used for one’s handicap.

A full explanation of the reasoning from the USGA:

Playing alone and necessary peer review: To further support the key System premise of peer review, scores made while playing alone will no longer be acceptable for handicap purposes. This change underscores the importance of providing full and accurate information regarding a player’s potential scoring ability, and the ability of other players to form a reasonable basis for supporting or disputing a posted score. (Section 5-1: Acceptability of Scores)

There’s no shame in playing alone, now, though, a USGA handicap may be a trickier proposition.