IN the Labor-held electorate of Sydney there are seven journalists to every plumber. In the Liberal-held seat of McMillan in Victoria there are 17 plumbers to every journalist, which is why the good people of Paddington will probably have to wait until Thursday week to get a tap fixed, but the denizens of Pakenham may not.
Journalists and plumbers both thrive on leaks, but beyond that they have little in common. They might have done once, when journalism was a craft, not a profession, and when its practitioners were called reporters, because that was what they did.
Nowadays it is largely a middle-class pursuit and some journalists have such a high opinion of their own worth that they think of themselves as insiders.
The hacks-v-dunny-diver ratio, otherwise known as the Kenny index, in honour of "the Dalai Lama of Waste Management" who stars in the film of the same name, is therefore as good a guide as any to Australia's geo-cultural divide, the tribal divisions reflected in where we reside.
In the limited number of seats where the insiders prevail, the issues that will drive votes at this election are a world away from the things that matter to the rest of the country.
The insiders lack the numbers to have much influence at the ballot box, but since they are the gatekeepers in the national debate they speak with a loud voice.
About 10 per cent of Australia's 20,000 journalists live in central Sydney or its eastern and inner-western suburbs in the seats represented by Labor's Tanya Plibersek and the Liberals' Malcolm Turnbull. One in five journalists lives in just five seats: Sydney, Wentworth, Melbourne Ports, Melbourne and Grayndler. Three are held by Labor, one by the Coalition and one by the Greens. The divide, however, is not political but cultural.
There are 13 federal electorates in what we might call the Chatter Zone: the seats where there are more journalists than plumbers. Here the Coalition has a clear majority, with nine seats; Labor and the Greens hold four between them.
A common cultural thread runs through them, however, that sets them apart from the rest of the county. One in five voters in the Chatter Zone casts their first vote for the Greens, almost twice the national average. A vote for the Greens is rarely cast in the expectation of changing the government. It is more a state of mind. The Chatter Zone is clearly a very progressive place.
Other census statistics confirm this is the case and offer an insight into the media's agenda, helping to explain why the media treats some ideas as feral while others are kept as pets.
In the seat of Sydney there is one same-sex couple to every 10 mixed couples. In the Chatter Zone as a whole, one couple in 35 is a same-sex relationship. In the rest of the country it is one in 175.
It is a sobering, or perhaps exhilarating, fact that every fifth adult you meet in the Chatter Zone will have a degree in the arts and humanities, more than three times as many as in the general population.
One in three residents declare that they have no religion; elsewhere it is one in five. Outside the Chatter Zone there is one de facto relationship for 10 registered marriages, inside it is closer to four in every 10.
The prejudices of the Chatter Zone set the agenda on ABC1's Q&A. Planetary warming? Check. Gay marriage? Check. The depravities of the Catholic Church? Check. Turnbull for Liberal leader? Check. It is an inner-city dinner where the only saving grace is the absence of couscous.
Does it matter if media people are different from the rest? Possibly not if we just expect the media to entertain us. No offence, but arts and humanities graduates are generally more amusing company than actuaries or dentists. The danger, however, is that the media becomes captured by their interests and regulated by their peculiar foibles, and that is indeed a problem.
It can distort the national debate and foster cultural bias in public broadcasting. There are pitfalls too for a commercial media company if its staff members forget who they are supposed to be talking to, and instead of broadcasting far and wide start narrowcasting to themselves.
Politicians too need to watch their step, recognising that applause from the media gallery does not necessarily mean they are serving their constituents well.
Consider a hypothetical election in a country we will call Media Land, which consists of the 29 federal parliamentary seats where half of Australia's 75,000 media professionals lived in 2011.
The Coalition is in government in Media Land with 15 seats; Labor holds 13 and the Greens one.
If Labor were to win Brisbane, however, one of the seats considered likely to go its way, the party would be able to form government with the support of the Greens. If the ALP defeats Adam Bandt in Melbourne, or if it were to retake Bennelong, another seat some believe is in play, it would govern in its own right.
In other words, Kevin Rudd may have a better chance of becoming the notional prime minister of Media Land than he does of winning a mandate from the other 121 seats.
It speaks volumes about Rudd's fascination with the media. It is an indication of the perils for the Labor Party of believing that the progressive liberal point of view should take precedence over the rest. It is a reminder of the folly of assuming that social conservatism would die out with Labor leader Arthur Calwell, who was replaced by Gough Whitlam back in 1967, and the arrogance of assuming that the tide of history was washing everything before it towards a progressive future.
Who would have thought it? The leader of the workers party may be more popular among the luvvies than the tradies. People with dirt under their fingernails may be less inclined to mark a Labor candidate's box than people with shiny pants. The bloke who reads the news on the telly may vote for Rudd, but the bloke who fixes the telly may not.