Petrol prices
From time to time I like to remind people about the national petrol price monitoring program. For example, when there’s a call for a review of fuel prices.
The Ministry of Business, Innovation & Employment (Economic Development Information) carries out weekly monitoring of “importer margins” for regular petrol and automotive diesel. The weekly oil prices monitoring report is reissued each week with the previous week’s data.
The importer margin is the amount available to retailers to cover domestic transportation, distribution and retailing costs, and profit margins.
The purpose of this monitoring is to promote transparency in retail petrol and diesel pricing and is a key recommendation from the New Zealand Petrol Review
The importer margin for petrol over the past three years looks like this:
The wiggly blue line is the week-by-week estimated margin; the shaded area is centered around the red trend line and covers 50% of the data. The margin had been going up; the calls for a review came just after it plummeted.
At the same site, but updated only quarterly, is an international comparison of the cost of fuel broken down into tax and everything else.
Thomas Lumley (@tslumley) is Professor of Biostatistics at the University of Auckland. His research interests include semiparametric models, survey sampling, statistical computing, foundations of statistics, and whatever methodological problems his medical collaborators come up with. He also blogs at Biased and Inefficient See all posts by Thomas Lumley »