Do you know how to perform a conversion between pounds and kilograms in your head on the fly?
Grocery stores may use conversion confusion to skew our perception of how pricey food is, according to a new study.
Researchers from Concordia University found in several experiments that consumers falsely believe products are cheaper when the price per pound is emphasized rather than the price per kilogram.
It could be one of the reasons why a perceived bargain in the produce aisle sometimes turns out to be less than one once you check your receipt.
“It’s a uniquely Canadian experience, because prices of produce here are displayed in pounds and kilograms at the same time,” Mrugank Thakor, a professor in the Department of Marketing at the John Molson School of Business, said in a press release. “But when you look at the receipt, all the prices are in metric (in kilograms).”
In Canada, the prices of certain goods, including some goods sold at the grocery store, are advertised by both the price per pound (lb) and per kilogram (kg).
Because a single pound is a smaller unit of weight than a kilogram — one kilogram is equivalent to roughly 2.2 pounds — this means the price per pound will always be smaller than the price per kilogram.
It’s that smaller number that Canadian consumers are looking for when assessing prices, without taking into consideration the unit of measurement, researchers found.
According to the government’s website, if both metric and Canadian imperial units are used to advertise a product sold in bulk such as produce, “the quantity must be stated on a receipt or similar document in one of the units at the price.”
METRIC VS. IMPERIAL
In the metric system, the unit of measurement used for weight is the gram and the kilogram, while the imperial system uses the pound.
Canada officially uses the metric system for the majority of our terms of measurement in industry, advertising, sales and other official capacities — such as all of our signs displaying speed limits as kilometers per hour instead of miles per hour.
But this wasn’t always the case.
Prior to 1970, Canada used its own version of the imperial system, which was referred to as “Canadian imperial units”, or sometimes just “Canadian units”. Canada’s version of the imperial system is almost identical to the imperial system still used in the US, with the exception of a gallon, which holds a slightly different volume of liquid in Canada compared to in the US
Although Canada began the switch to using the metric system in 1970, the familiarity that many Canadians had with the imperial system meant that many products were permitted to continue displaying prices by imperial units along with metric units.
One area in which this is common is when Canadians are buying produce or vegetables.
According to the government’s website, stores “must use metric units when displaying the price of fruit, vegetables, nuts and other food sold in bulk (unpackaged) on signs as well as in print and online advertising,” but that they can “also choose to include Canadian (imperial) units along with the metric units.”
THE ILLUSION OF “CHEAPER”
Thakor, who co-authored the study published earlier this year in the Canadian Journal of Administrative Sciences with his former students Yonglan Liu and Rui Chen, said the reason many products are still advertised in imperial units in Canada is because it makes the price “look better.”
“Prices per pound look cheaper because the number is smaller, prices per kilogram (are) more expensive because the number is bigger,” he explained. “Although retailers display both prices, the prices in pounds are in larger font and the prices in kilograms (are) in smaller font.”
The need to find deals at the grocery store has been top of mind for Canadians as of late, with prices spiking in 2022 and showing no signs of receding, all while grocers continue to rake in high profits.
The study authors, who are focused on produce prices, say emphasizing the per pound price is a way grocery stores may be intentionally skewing consumers’ perceptions of what is cheaper.
In one experiment, they deliberately increased the font size of the per kilogram price of produce instead of the per pound price as many grocery stores do, and found consumers paid far more attention to the price in kilograms than they had before.
Along with adjusting the font, researchers conducted several other experiments to measure the perceived price of produce.
When participants were served with strawberry prices at $4 per kilogram versus strawberries priced at $1.82 per pound, they were more likely to rate the $4 strawberries as more expensive, despite the fact that they were actually the exact same price — just expressed through different measurements.
Consumers asked to draw up a budget for grocery shopping were also more likely to put more of their budget towards producing when the prices were given to them exclusively as per pound, versus when they were given to them as per kilogram.
Another test found consumers perceived stores as more expensive if their flyers emphasized per kilogram prices versus per pound pricing.
“While there have been numerous studies looking at spending habits using different currencies, there have been very little done using different units of measurements like pounds and kilograms,” Thakor said. “It was thought that over-reliance on the size of the numerical component happened only with unfamiliar units such as obscure currencies – we show that it happens even with everyday pricing units.”
If you’re looking to save money, it might help to pay more attention to both the per pound and per kilogram measurement, so that you aren’t surprised at the cash register.
But while the results suggest consumers may be spending more than they intended due to their perception that food advertised this way is cheaper, Thakor noted that one unintended side effect could be consumers choosing healthier options more.
“Using imperial units such as pounds makes fresh produce look cheaper than it really is, and it might be offline consumers away from frozen produce, which could possibly provide the same nutritional benefits at lower cost,” he pointed out. “But on the other hand, this tactic likely encourages greater consumption of fruits and vegetables rather than processed foods. So consumers may misperceive prices as lower than they actually are, but that misperception may actually work to help consumers stay healthy.”