Gasoline prices are high and rising. Anecdotally, they seem to be increasing at the pump by the hour. And indeed, in nominal terms they are now the highest they have ever been in the US (this is true with both the AAA daily price level and the EIA weekly price level). At over $4.10 per gallon, the price now exceeds the peaks briefly hit in 2008, 2011, and 2012. And it’s looking like this peak might not be so brief.
But we all know you can’t compare nominal dollars over long periods of time. We need some context for this price! Plenty of news stories provide what they think is the right context: adjust it for inflation! For example, USA Today reports that today’s price “would come to around $5.25 today when adjusted for inflation.”
$5.25: that’s a pretty concrete number. But it’s not really useful. OK, so clearly that’s higher than the current price, about 20% higher in fact. Still, it doesn’t really give us the right context.
As I argued in a previous post on housing costs, inflation adjustments aren’t always the best way to contextualize a historical number. Yes, when you want to compare income or wages over time, it’s good to adjust for inflation. It’s necessary, in fact. And a good economist will always do that.
However, when comparing particular prices over time, it doesn’t really make sense to adjust for other prices. All you are really saying is “if the price of gasoline increased at the same rate as the average price level, here’s what it would be.” Perhaps slightly useful, but it doesn’t really get at the thing we’re really try to address: is gasoline more or less affordable than in the past?
The best approach is to adjust the prices for changes in wages or income. Which measure of wages or income you choose is important, but it’s the best adjustment to make. No need to make any inflation adjustments, are worrying about whether the index you choose is properly accounting for quality changes, substitution effects, etc. If you want to know how affordable something is, compare it to income.
Here’s what I think is the best simple comparison for gasoline, which I’ll explain it below. In short, it tells us how many minutes the average worker would need to work to purchase one gallon of gasoline.
Since the price of gasoline is rising sharply every day lately, my chart will surely be out of date very soon. But right now, it’s the most current data I could provide with a comparable historical series: EIA weekly data current through March 7th, 2022 (Monday). We can see that at current prices, it takes about 9 minutes of work at the average wage to purchase a gallon of gasoline. At the peak in 2008, it took over 13 minutes of work to purchase a gallon, and it fluctuated between 10 and 12 minutes of work for much of 2011-2014.Continue reading