Need to know if your MP is giving you value for money? Just ask Jordan.

A chill wind of fear will have blown through the corridors of power in Wellington with the publication of this Sunday Herald story about Green MP Mojo Mathers' decision to travel to take part in a radio show about people with disabilities.

I mean, you may very well think that this is something that New Zealand's sole deaf MP might have a special interest in participating in. And while the show in question, on a Wiararapa community access station, probably won't change the world, I have no doubt it is an important  resouce for a group that is shut out of most mainstream conversations.

But then again, you're not a gimlit eyed crusader for the taxpayer, like Jordan Williams of the "Taxpayers' Union" (and note to Patrice Dougan and the subeditors at the Sunday Herald - they aren't so stingy that they've abandoned the possessive apostrophe). Because he's on the hunt for elected representatives who are frittering way public cash with expensive, yet pointless, jaunts around the nation.

Which creates something of a dilemma for our leaders in government.

I mean, how is John Key meant to know whether it is "value for money" for him to travel on the comparatively expensive Wellington-Dunedin route (bringing with him his staff and Diplomatic Protection Squad minders, of course), take a Crown limo the 70-odd kilometer round-trip into Dunedin city from the airport and tie up police time to deal with the inevitable protestors who turn out at his appearances, just so that he can meet a few children at a kindergarten and visit a brewery?

Much less work out if he's doing right by the taxpayer to bring his entourage to Queenstown (and how did they manage to get there from Dunedin - not by bus, I'm sure!) in order that he can give a speech to a small group of business folk and have a round of golf at the Hills course in Queenstown. I mean, exactly where did they all stay while they were in that holiday resort? How much did it cost? How fluffy were the towels? Did anyone order anything on room service? Because it's us that's paying for all this!

Fortunately, our political overlords may rest easy. For the Taxpayers' Union has issued a simple and handy formula for determining whether such rambles are acceptable. Applying this formula will in all cases determine the matter.

First, calculate the total cost of the exercise.

Then, calculate the benefits in terms of the number of people engaged with and the quality of that engagement.

Finally, apply the partisan discount factor to each of these variables. If the representative in question is from a party for which you are a thinly disguised front organisation, you should both down play any expenses ("of course it's going to cost money for the PM to do his job!") and puff up any outcomes ("it's the PM's role to be out-and-about in the community! The extra attention brought to the NZ Open will help establish it as a world-class event!").

However, if the representative is from a party with which you have deep ideological disagreements and so are doing your best to keep out of government at the next election, you both maximise the expense ("flights could have been as much as $199 each way!") and down grade the result ("there were probably only five people listening!"). Of couse, you don't need to prove that this was the case - you just know it was because, well, you've set up an organisation and given it a name and have some members (but you won't say how many) and so whatever you choose to say is "news".

Because that's what speaking up for "the taxpayer" is all about.