Forget those instant computer predictions. Throw out those political analysts whose tales are already stale by the 11 p.m. news on election Tuesday. You're in Cambridge, and election night isn't over, not by a long shot. Here, you've got nearly a week after elections to figure out who's winning and who's losing.

The reason, of course, is Proportional Representation-that intricate (some would say Byzantine) electoral system which only Cambridge, alone of U.S. cities, still uses. Some 25 cities used it earlier in this century. They adopted it so minorities would have a better chance of election; they generally got rid of it when unpopular minorities got elected. Now, only in Cambridge can you savor the weeklong PR count.

It'll be going on again today, perhaps far into the night, at the Longfellow School auditorium-a 15-minute walk down Broadway from Harvard. Depending on the hour of day, anywhere from 150 to better than 300 people will be jammed into that auditorium, doing and watching the PR count.

The count, no matter how well organized it may be, always strikes a newcomer as something like an especially chaotic county fair: children run about, ladies gossip, politicians caucus, and loudspeakers blare.

But most of the people there know what they're doing; at least, they know why they're there: to find out which nine city councillors and which six school committeemen the City's voters elected last Tuesday. With luck, more than a little of it, they'll finish the job tonight, and go home after a count which has lasted four days and cost the city some $6500-probably not much more than it would cost under other electoral systems, since PR climinates the need for primaries and special elections. But if they don't get through the last rounds of the count tonight, counters, candidates, and "watchers" will be at it again next week.

To understand what's going on at the count, it's helpful to look first at what a citizen does when he votes under PR in Cambridge. Two long paper ballots-this year, they're blue for City Council, pink for School Committee-are handed to him at the polls. On the ballots are listed the names of the candidates. Instead of marking an "X" beside his choices, the voter ranks his preferences (1, 2, 3, etc.). In theory, he could indicate his 26th choice for a council seat, but most voters confine themselves to a maximum of four or five choices.

After the polls close, the ballots are locked up, and then brought next morning to the school auditorium. There, just before 8 a.m. the 100-odd election clerks begin a first, "unofficial" count of the "number one" votes for each city council candidate. The City has eleven wards, each with five precincts-so there are eleven little cubicles on one side of the auditorium, to allow the first precinct of each ward to be counted simultaneously, etc.

As the count of "number ones" continues throughout the day, candidates and their pollwatchers hang outside each little cubicle, keeping a running count much as they do under the usual election systems. Around five p.m., the count is over. and candidates, media, and hangers-on crowd to get the official announcement of this "unofficial" count. This "unofficial" count is merely a device to-speed up the "official" first count the next day, when the pre-sorted ballots are actually stamped for one candidate or another.

With luck, by the middle of Friday, the Election Commission will have an "official" count of number one ballots for the City Council. Then, the real fun of PR begins.

Under the system, each candidate must have a certain quota of votes in order to be elected. The quota is set by dividing the total number of votes cast by the number of seats to be filled plus one. Then, add one vote to the quotient and there's the quota. The idea behind sitting the quota at this level is to make it low enough for candidates supported by a minority group to get elected, and high enough to make the elections more than a matter of chance.

This year, about 25,000 voted in the City Council election, making the quota approximately 2500. As he almost always does, Walter J. Sullivan ran highest; he was the only candidate to make the quota from his "number ones." As an example, say Sullivan got a hypothetical total of 3750 "number ones" (slightly higher than his actual count). Thus, he is 1250 over the quota.

In the next step of the count, the 1250 surplus Sullivan votes will be redistributed by taking every third Sullivan vote from the envelopes in which they are kept, by precinct, after the first count, Each of the 1250 votes is then put into the pile of whatever candidate is marked "number two" on the ballot.

The redistribution of the "surplus" of candidates who make the quota is one half of PR's reshuffling of votes; the other half is the elimination of the candidates ranking lowest at any one time, and the redistribution of their votes to "number two" candidates.

The following shows what this redistribution can mean for one voter's ballot:

It's an unlikely combination, but let's say you voted "number one" for Sullivan, "number two" for Peace and Freedom Party candidate Cynthia F. Kline, and "number three" for incumbent councillor Barbara Ackermann. Thus, your vote would be counted for Sullivan in the first round and, since he met the quota in that round, perhaps drawn and placed in Miss Kline's pile. Since she was a weak candidate (pulling only some 250 "number ones") she would soon be eliminated. Your ballot would then go to Mrs. Ackermann's pile, and rest there, helping her to meet the quota.

This continual counting and transfer of ballots-both for Council and school committee-goes on in an atmosphere somewhat akin to a blend of a ladies'coffee circle, Suffolk Downs, and Chapter 7 of The Last Hurrah,

At the center of it all are the ballot counters-some 120 of them, mostly elderly ladies, half of whom are Democats and half Republicans (in order to keep the non-partisan election nonpartisan). In between counting ballots, some just sit quietly and munch the free coffee and doughnuts or stare at the bleak walls of the auditorium, but most gossip-about their children, their illnesses, the weather and, this year, the demonstrations at M.I.T. (which they didn't seem to like).

Some of those countres take a vacation from their usual jobs in order to be present for the social festivities of the count. But others come for another simple reason: the $12 a day the job pays. "I need the money, What else can I say?" comments a sixtyish lady in a flowered dress.

Though the job may once have been a plum, fewer people want it these days. The Election Commission has difficulty finding enough counters-particularly the necessary Republicans-in a City which is mostly Democratic. "It's harder to find people than it used to be. We don't have enough to draw from. What with Model Cities and everything, there are just so many other jobs and so much money around," says one of the supervisors.

As the counters go about their work, candidates and their count-watchers peer in on them-sometimes intently, sometimes lackadaisically-from over the iron pipe railing which separates the counters from everybody else. Watching the ballots pile up and listening for announcements of precinct results, the candidates continually reappraise their situation. Witness Harvard Ed School student Francis X. Haves, during the first count of ballots for him and the other School Committee candidates:

"I think I'm going down on this count. I've been watching the piles." (Laugh) "I knew I should have gone to that class instead this morning."

The count has a rhythm of its own; at first the moments of activity are few and far between as ballots are laboriously counted and stamped. Then, as the redistribution picks up speed, the flurries of activity come closer together, though waiting for the next count is always an infinity for any politician, anywhere. The onlookers join in the handicapping game, in particular attempting the difficult task of determining which candidates will have number two votes to give to which others, or as they put it. "who'll be feeding whom." Conversations go like this:

"Clinton? You watch: he's going to get Sullivan votes. He'll get two, there hundred of Walter's surplus."

"I'll tell you who's in trouble-Mahoney. I just saw The Professor [incumbent Thomas H. D. Mahoney is an M.I.T. professor] and I told him, You'd better watch out, there's not going to be any Crane surplus to go around this year."

During the redistributions, counters call out the name of the candidate to whom each ballot will go before they place it in that candidate's pile. "VUH-LEW-CHI," the cry comes. The pencils of a dozen candidates and watchers crowded around make another mark next to Al's name on the sheets where they're tallying the redistribution. "We're getting plenty but maybe you could use some more votes. We'd slip a few extra ones in for you-but there's witnesses," A Vellucci backer jokes with another candidate.

And so it goes, for hours which soon stretch into days. As the count grinds along, some candidates begin to complain: "What's the matter with the Election Commission? Don't they understand this system?" Council candidate Daniel J. Clinton inquires of Eddie Martin a man of no small local importance who (a)-writes the City stories for the Cambridge-Somerville edition of the Boston Record-American; (b) -serves on the Cambridge Housing Authority; and (c) -is a good friend of Councillor Al Vellucci.

No, they don't. They're always asking me" replies PR veteran Martin, who then returns to his tally sheet, as if preparing his bets for the eighth race.

Much of the grousing about the count itself is probably unfair. In fact, today's counts are, by general sentiment, models of efficiency compared to those done in the first years after Cambridge adopted the PR system in 1941. In one election then, it took nearly a month to get the results.

Complaints about the count probably only reflect a deeper discontent with the PR system itself, which has never been universally popular in Cambridge. On four occasions, anti-PR groups have put on the ballot referendums on whether to retain the system. Each time, however, voters approved of PR; the last time, in 1965, by a 2500-vote margin.

The discontent remains, though, particularly among some of the socalled "independents." They feel the system unduly aids the other of the City's two political factions-the Cambridge Civic Association, the local "good government" group. "The only minority PR protects is the CCA," said one veteran of an anti-PR campaign, arguing that the CCA's loose system of endorsement gives them an edge on the independents, who are not even that well organized.

The complaint that PR doesn't really help minority groups seems to be not quite true. Under PR. Cambridge's blacks, for example, have gained seats on the council and school committee which they probably would not have gained under any other electoral system, save a ward system gerrymandered in their favor. At the same time, other minorities such as Jews and even Yankees have gained seats though it would be difficult to say if they would have got more or less under another system.

The counterpart of minority representation is, however, often a Cambridge City Council which cannot muster a cohesive majority. Though PR candidates run at-large, the system places a premium on "number ones." To get them, candidates most often appeal to a small group. Once on the council, they are often more interested in divvying up the current pie of City services among their voters than in planning much expansion of said services.

No "perfect" electoral system exists, however; PR, whatever its faults, does succeed in making Cambridge's political system mirror all the strains and divisions running through the City. As such, it seems to have found a home here. For some years to come, Cambridge will probably still be counting its ballots by the weekend after election Tuesday.