The system of proportional representation (PR) used in Cambridge city elections will almost certainly be challenged in a referendum this November, State Rep. Levin H. Campbell '48 (R-Cambridge) said yesterday.

A bill permitting the referendum passed its last crucial legislative hurdle Wednesday when the State House of Representatives approved it 145 to 73. The Senate approved the bill Monday. Now only formal enactment remains before the bill can be presented to the governor for his signature.

'Unfortunate Decision'

Campbell, who favors PR, introduced a motion to kill the bill. He attributed its defeat to the "unfortunate decision of the Democratic leadership, for various political reasons, to make the bill a party issue." Rep. John J. Toomey (D-Cambridge), who supported the bill, said he has opposed PR since he was elected to the City Council in 1932. He called it a system of "unproper representation."

Another opponent of PR, Frederick C. O'Connor, president of the Cambridge Young Democrats, hailed the House action as a step toward the end of "mass confusion and majority control."

Confusion

"Much of the confusion in PR voting is caused by attempts to trick the system," Dana S. Hanson, executive secretary of the Cambridge Civic Association, suggested. He said the CCA, which favors PR, would take an active part in supporting it in the referendum.

Campbell said that PR has worked well in Cambridge because the city has many minority groups. Contrasting the system to Boston's plurality elections, he said it permits representation of all points of view in proportion to the size of each group.

PR has been challenged four times in the last 12 years.