Expert Commentary

# Using ‘per capita’ to describe data: 4 things journalists need to know

An economist and a statistician help us explain the right and wrong ways to use 'per capita' to describe data related to economics, public health and other news topics.

(The Noun Project)

If you report on economic research and government reports, you’ve almost certainly encountered the statistical term “per capita,” a Latin phrase that means “by heads” or, essentially, “per person.”

A country’s gross domestic product, a popular measure of economic health, often is expressed in terms of per capita — the value of goods and services produced by that nation per individual within the population. The United States’ GDP was just under \$26.5 trillion during the first quarter of 2023, according to the U.S. Bureau of Economic Analysis. The GDP per capita: \$79,148.

Scholars, statisticians and government officials also use the term when examining data for a range of policy issues, including public health, education funding, local crime and public transportation usage. A researcher might, for example, track per capita sugar consumption in a certain city to gauge how much sugar each resident consumes in a given year, on average.

Although per capita is a specific type of rate, news outlets sometimes use it incorrectly to describe other rates. Also, journalists frequently report on data without breaking it down per capita, even when doing so would provide audiences with crucial context.

One of the most common mistakes news outlets make is using “per capita” to describe a number per 1,000, 10,000 or 100,000 people. For instance, if a government report estimates the number of police officers working in a particular state is 2.3 officers for every 1,000 residents, it would be incorrect to report this as the number of officers per capita. The per capita rate would be 0.0023 officers per resident.

To help us explain the right and wrong ways to use the term in news coverage, we teamed up with two experts — economist Steve Landefeld, the former, longtime director of the U.S. Bureau for Economic Analysis, and statistician Jing Cao, a professor in the Department of Statistics and Data Science at Southern Methodist University.

They suggest journalists keep these four things in mind:

### 1. Remember that per capita numbers represent averages.

Per capita figures represent the average number of something for all people within a population, Landefeld and Cao explain.

If you were to report on per capita health care expenditures for each state, for instance, you’d provide audiences with the average amount of money each person spends on health care, by state. Per capita health care spending in 2020 ranged from \$7,522 in Utah to \$14,007 in New York, a report from the U.S. Centers for Medicare & Medicaid Services shows.

### 2. If a research paper or government report doesn’t break down a number per capita, do the calculation yourself by dividing the number you’re interested in by the target population.

Government agencies in the U.S. report many types of data on a per capita basis. But if they don’t do that for the data you’re examining, Landefeld and Cao recommend doing the math yourself. To calculate per capita, take the number you’re interested in and divide it by the population involved.

“It’s a pretty straightforward concept,” Cao says. “You just need to know the population.”

Here’s a quick demonstration. Let’s say a city government reports that its residents threw away 55,200 tons of garbage in 2021. To find out how much garbage each resident threw out, on average, you’ll need to look up or ask for the city’s population that year. Let’s say 710,000 adults and children lived in that city in 2021.

Here’s the per capita calculation:

Tons of garbage per capita = 55,200 tons of garbage/710,000 residents = 0.08

To help audiences better visualize the amount thrown out, consider reporting it in pounds per person, instead of tons. In the U.S., there are 2,000 pounds in a ton. In this city, each resident threw away an average of 160 pounds of trash in 2021.

### 3. Don’t confuse per capita with other types of rates.

Researchers and public health officials often report the rate of COVID-19-related deaths as the number of deaths per 100,000 people across a country or other geographic region. Some news outlets have incorrectly described these rates as “per capita” death rates.

In recent years, journalists have also incorrectly referred to rates of identity theft, shootings, home sales and the concentration of fast-food restaurants in an area as “per capita” rates. Some of that coverage focuses on data expressed as a number per 10,000 people.

“When the number you’re reporting is in conflict with the definition of the word you’re using [to describe it], I would, in that scenario, drop ‘per capita,’” Cao says.

Journalists should refer to a rate as “per capita” only when it represents a per-person average.

“Reporting a number like 80 for every 100,000 [people] is not really per capita,” Cao says. “As a data person, if I saw this, I would probably pause and think about, ‘What does this mean? Why is this person using ‘per capita?’”

To ensure accuracy, consider simply telling audiences what the rate is, Landefeld adds.

“Call it what it is: ‘80 per 100,000,’” he says.

### 4. When comparing countries, states or regions, put data into context by including per capita and median numbers.

When journalists report on a key number such as a country’s GDP without providing per capita GDP, they neglect to add important context. It’s also tough to compare two or more countries’ economic prosperity without that information, considering populations can vary significantly, Landefeld and Cao note.

“Especially when you’re making comparisons across countries, at a minimum you want to look at per capita trends,” Landefield says.

A case in point: In 2021, America’s GDP, \$23.3 trillion, was the world’s highest, followed by China‘s GDP of \$17.7 trillion, according to the World Bank. But a look at each nation’s GDP, broken down per person, reveals stark differences in their average citizens’ living standards.

China’s population, 1.4 billion in 2021, vastly outpaces America’s at 332 million. As a result, China’s per capita GDP is much smaller — \$12,556 per person compared with \$70,249 per person in the U.S. that year.

When you look at the data this way, you see that even though China’s GDP was 27% smaller than the U.S. GDP, its GDP per capita was not even one-fifth of America’s GDP per capita, indicating the average person living in China had a significantly lower standard of living than the average person living in the U.S.

Landefeld and Cao urge journalists to include median GDP per capita in their coverage. The median is the middle number in a series or list of numbers arranged from largest to smallest, or smallest to largest. Half the numbers are smaller than the median and half are bigger.

Landefeld and Cao say the middle number on a list ranking a country’s citizens by income will give audiences the best sense of how an economy is performing across segments of the population. Because GDP per capita is an average, it obscures the distribution of wealth. A country where every person has the same standard of living can have the same GDP per capita as a country with lots of very poor and very rich people.

“Each number only gives you one peek into the whole thing,” Cao explains. “The median is always more representative.”

Two economists who won The Indigo Prize in economics in 2017 have also stressed a need to spotlight median per capita GDP.  In their winning essay, Diane Coyle, a professor at the University of Cambridge, and Benjamin Mitra-Kahn, an assistant commissioner with the Australian government’s Productivity Commission, propose a more accurate way to measure economies.

“The public debate about the economy currently focuses on growth in total GDP, or occasionally per capita GDP,” Coyle and Mitra-Kahn write. “A focus on [wealth] distribution is needed. Statistical agencies could easily make median per capita GDP the standard headline figure in regular press releases.”

Cao notes this context is particularly useful for people who rely on journalists to help them make sense of economic trends.

“When you report something, context is No. 1,” she says.