The tabloids are leading off today with news of a likely pay rise for federal politicians.

There has been no official release from the Remuneration Tribunal inquiry into parliamentarians pay. It seems though that some well-sourced backgrounding has been going on. Steve Lewis reports the prime minister may get a $90,000 pay rise to $470,000 and ordinary backbenchers an increase from $140,000 to $180,000.

It is not good timing, with the recent announcement of cuts in the mid-year economic outlook. Then again, it is never a good time to increase politicians’ pay.

If the pay rises are funded by reducing the multitude of allowances and entitlements that currently apply, it is unequivocally a good thing. There are numerous such entitlements, set out in this publication from the Parliamentary Library. The various entitlements are a capricious and hidden supplement for politicians pay.

They are capricious because they benefit different politicians in very different ways. Politicians who read books, like Senator Scott Ludlum, clearly get more out of the $4870 book allowance than those who can’t be bothered reading. Some politicians use their overseas study trips actually to study; others demonstrate rather less evidence of ever having actually learned anything from these trips. It is surely the case that an entitlement to a mansion on the north shore with expansive harbour views would be worth a lot more to an ambitious former solicitor from suburban Sydney than to a rather different former solicitor from Melbourne with a modest house in Altona.

They are hidden because for the most part the public does not get to see how the entitlements are being used. Over time they have grown up as a way of sneaking politicians pay rises through the back door.

Rationalising the allowances and sweeping them into politicians’ pay packets would be fairer and more transparent. If though there is a component of the rise based on an assessment of what politicians are worth, the Remuneration Tribunal will be treading into far trickier territory.

The truth is, nobody knows how much a politician is worth.

Former Howard government Peter Reith pointed out a little while ago that clichés like “pay peanuts, get monkeys” don’t help. They attract an immediate riposte from the cynics: “We know we will end up with monkeys, so why not pay them peanuts.”  Not only that, but few politicians are motivated by money alone: it is the prospect of power and influence that gets their juices flowing.

Measuring how well politicians exercise their role in governance is subjective. In our political system, at any one time roughly half our elected politicians loudly proclaim the other side could not be trusted to run a chook raffle let alone a country. If we were to add up all the negative claims that oppositions make about governments, and vice versa, then obviously all of them are outrageously overpaid. If on the other hand we added together all their positive claims about how good they are, were, or would be at running the country, they deserve to have their salaries doubled instantly.

The extent to which you can measure the “workload” of an average MP or senator is also dubious. It depends on the parliamentarian.

Most MPs choose to go, when possible, to community functions in their electorate, deal with constituents day and night, serve on committees diligently, read a fair bit of the legislation on which they vote (nobody reads it all, that would be impossible). Most senators, although they don’t have the same pressures of electorate work, are hugely diligent in their scrutiny and review function.

Some parliamentarians though are rather more casual: meet constituents rarely, sit on committees in name only, and vote the way they are told without ever bothering to think. This kind of parliamentarian is rare, and the voters or their party catch up with them eventually, but they have been known.

The point is, the amount of work that each parliamentarian does is really their choice. So setting a salary based on some theoretical work standard does not help.

Similarly, productivity measures for politicians are impossible. One shudders to think of a productivity measure like “amount of legislation passed in one year” — at a time when the regulatory burden is growing, the last thing we need is an incentive for politicians to pass even more.

Then there is the Singapore solution, of tying parliamentary and public service salaries to the rate of economic growth. If growth falls, they take a pay cut. Although this has the advantage of being an external rather than a subjective measure, it won’t satisfy those for whom economic growth is a misleading measure of national performance. You can’t see the Greens, for example, agreeing to this as a measure of the worth of parliamentarians.

In the end, it comes down to a political judgement about what the Australian electorate will be happy to accept. If there is a pay rise for politicians, it will need to be presented with trade-offs — not only a reduction in the number and complexity of allowances, but also greater transparency in the use of any allowances and entitlements that remain.