ATLANTA (Reuters) - The U.S. National Mediation Board has proposed a sweeping rule change that would base the outcome of union elections at airlines and rail companies on the majority approval of people who vote, a move that could increase the odds of unions winning such contests.

The proposal, if implemented, would change current procedures dating back 75 years that require a majority of an entire work group to approve unionization. That policy effectively counts members of a group who don't vote as 'no' votes.

"It's a good turn for unions because it makes the election process fairer and it resembles more closely national political elections," said Gary Chaison, professor of industrial relations at Clark University in Worcester, Massachusetts.

In its proposal, posted to a government website on Monday, the mediation board said the current procedure under the Railway Labor Act seems "at odds" with basic tenets of democratic elections.

"The NMB believes that this change to its election procedures will provide a more reliable measure/indicator of employee sentiment in representation disputes and provide employees with clear choices in representation matters," the board said in the proposal.

ENCOURAGE VOTER PARTICIPATION

The proposal added that the change would discourage worker non-participation in union elections.

The chairman of the three-member mediation board, Elizabeth Dougherty, disagreed with the rule change, saying it would be "an unprecedented event" in the labor board's history. She added there was a question as to whether the NMB had the "statutory authority" to reverse the current policy.