Census overcounted Puerto Rico, hinting at larger population loss

The U.S. Census Bureau announced Tuesday that it overcounted the population of Puerto Rico by 5.7%, which raises questions about how much its population actually fell over the past decade.

In 2021, the Census Bureau reported that Puerto Rico’s population fell 11.8% to 3.3 million over the past decade, which was marked by multiple crises like bankruptcy, earthquakes and a series of hurricanes, the worst of which was Hurricane Maria in 2019.

On Tuesday, the bureau announced that a post-enumeration survey – which checks the accuracy of census by independently surveying samples on the island – found that the 2020 Census overcounted Puerto Rico by 5.7% or 174,000 people.

According to the report, the finding is not statistically different from the 4.5% overcount of Puerto Rico in the 2010 Census.

“Understanding the devastation caused by Hurricane Maria, we adapted our operational design to count Puerto Rico as we prepared for the 2020 Census,” said Census Bureau Director Robert L. Santos in a statement.

“We will continue to collaborate closely with key stakeholders in Puerto Rico to work toward an accurate count for future censuses.”

The majority of overcounts were due to duplicate records. The estimated rate of erroneous enumerations in the 2020 Census was 9.8% or 319,000, including 9.1% or 294,000 duplicate records.

The rate of erroneous enumerations due to duplication on the U.S. mainland is only 1.6%. A classic example of duplication is when a college student who filled out a census form at his school is also claimed as a member of the household by parents back home.

Mario Marazzi, the former executive director of the Puerto Rico Institute of Statistics and a member of the Census Scientific Advisory Committee, told NBC News that duplication in Puerto Rico could be attributed to cultural factors.

Spanish-speaking people often have two last names but “may not be reporting their names consistently in every form,” since there’s not always space for it, said Marazzi.

Another reason could be how dates of birth are written day-first in Spanish, compared to month-first in English.

The post-enumeration survey found that overcounts were more commons for younger populations – 3.6% for ages 30 to 49, compared to 9.7% for ages 50 years and older.