Americans’ love for their pets is apparent in dog parks and grooming parlors, on cat videos and pet food price tags. But just how many pets we love is less clear.
Google the U.S. pet population, and you’re quickly confronted with two oft-cited, and contradictory, sources. The American Pet Products Association found that 68 percent of U.S. households owned some sort of pet in 2016 — “equal to the highest level ever reported,” it gushed in the executive summary. Among those pets were about 90 million dogs and 94 million cats, the group said.
The American Veterinary Medical Association recently reported that 57 percent of households had a pet at the end of 2016, a figure the group characterized as having only “inched up” from its previous survey in 2011. The overall pet population, AVMA said, included 77 million dogs and 58 million cats — significantly lower than what the pet trade group cited.
These dueling digits matter nothing to the kitties and doggies that occupy our sofas and our hearts. But they’re important to many humans. Pet companies want to how much they might be able to sell. Veterinarians need to know how many patients to expect, and veterinary schools must determine enrollment numbers and course offerings. Whether people own pets can influence where they decide to live, or even whether they have children.
“For me, as an academic, I’m offended by the fact that everyone is running around using numbers” that vary so much, said Andrew Rowan, a former chief executive of the Humane Society International and a longtime scholar of pet demographics. “You can’t really make public policy decisions in the absence of data.”
It turns out there are other, stronger data from surveys that don’t appear at the top of search engines, and they find far lower pet ownership rates than the pet industry group’s record high figures. The Simmons National Consumer Study, which surveys households annually, found last year that 53 percent owned pets, figures that suggested at least 77 million dogs and 54 million cats, or about the same as the veterinary association.
And the U.S. Census Bureau’s American Housing Survey, which asked about pet ownership in 2013 and 2017, most recently reported that 49 percent of households included pets.
Why the discrepancies? Methodology matters. Both the industry and veterinary groups publish population figures in enormous tomes that drill deep into spending on pets, where people get pets and what kinds of pets they have. And both recruit respondents using internet “opt-in” panels, an increasingly common method that’s cheaper than randomized mail, telephone or in-person methods. Yet even though responses are typically weighted to match U.S. demographics, experts say such samples may not produce a representative picture. In addition, surveys focused heavily on one topic can also have a bias that’s hard to shake — in this case, toward pet owners, who are more likely to take a survey on pet ownership.
“When it comes to opt-in online surveys, you never really know what you are going to get,” said Robert L. Santos, chief methodologist at the Urban Institute, a think tank. He noted that in 2013, the American Association for Public Opinion Research warned that researchers should avoid this method for estimating populations.
The pet products association, which performs its survey every two years and had 22,000 respondents in 2016, used mail surveys until 2010 — and that’s when its ownership estimate jumped from 62 percent to 68 percent. Although its most recent report advises readers against “direct comparisons” between the mail and online data, its executive summary and news release do just that, touting record levels of pet-owning households and “significant” increases in dog ownership between 1988 and 2016.
Anne Ferrante, APPA’s senior vice president for member relations and business development, said the association believes the switch from mail to web was responsible for the large increase and added that researchers sought to combat bias by tracking which types of people completed the survey. The over time comparisons were highlighted because members wanted them, “so we included it to ensure accuracy in data interpretation,” she said.
The veterinary association, which conducts its survey every five years and had 41,000 respondents in 2016, switched from mail to internet in 2011. But the group’s chief economist, Matt Salois, said the most recent report is “more sophisticated” than the previous one because it targeted non-pet owners and weighted better for factors like geography and gender.