More than a quarter of New Jersey’s population lives in areas that will be hard to count as the Census Bureau begins its once-a-decade survey.

The state’s two largest cities are most in danger. An analysis by The Associated Press found that in Newark, 99.62% of the population lives in tracts that are at risk of being undercounted in the 2020 Census. In Jersey City, that number is 80.12%.

Obtaining an accurate count is critical because the census determines who gets $1.5 trillion in federal spending and decides which states gain or lose congressional seats. If states are undercounted, they can lose funding for highways, school lunches, crime victim assistance and many other programs.

A Census Bureau metric, called a low response score, classifies Newark and Jersey City as “hard to count” based on a variety of factors. For example, both cities have a lot of renters — mobile residents mean they’re harder to track down. They both have large communities where people don’t speak English at home. And many of these tracts have poor access to the internet.

In 2010, 62.3% of Newark residents sent in their census forms. The national response rate was 74%. Jersey City fared better, with 66.9% of its residents responding. This year, the Census Bureau predicts a 60.5% response rate across the nation.

What’s at stake?

Undercounted areas can get shortchanged when it comes to divvying up federal dollars. If everyone is not accounted for, areas in the state may not qualify for aid in the first place. Even if the geographic area qualifies for federal funding, it may receive less than it deserves.

If there is a statewide undercount, New Jersey could lose a congressional seat, because representation in Washington is dependent on the state’s share of the national population.

“Our share has been declining. You stand to lose if you’re not growing not as fast as the nation,” said James W. Hughes, dean emeritus of Edward J. Bloustein School of Planning and Public Policy at Rutgers University.

Efforts to combat undercounting

The decennial census attempts to count every single person in the country. In 2020, the process will largely be conducted online to save money.

Beginning in March, households will receive a mailed invitation to participate in the census online or over the phone, using a toll-free number. The online and phone questionnaire will be available in English and 12 other languages (Spanish, Chinese, Vietnamese, Korean, Russian, Arabic, Tagalog, Polish, French, Haitian Creole, Portuguese and Japanese).

Residents who don’t respond either by phone or online by early April will receive paper forms in the mail. If there are no responses by late May, the Census Bureau will send census-takers to knock on doors.

“We’ve learned from 2010 that one of the fastest groups of undercounted people is children under 5,” said Jeff Behler, regional director of Census Bureau’s New York region. Immigrants, communities of color and people whose first language isn’t English are also groups that have historically been undercounted, Behler said.

To reach these communities, the Census Bureau has partnered with businesses and other facilities that people trust, including churches, bodegas and mayor’s offices. As of this week, Newark has 138 partners and Jersey City has 94.

“We realized that the federal government might not be the best messengers,” Behler said.

Experts say the Trump administration’s effort to ask about citizenship on the questionnaire may scare off immigrants who live here without documentation. Although the effort failed, opponents of the question say damage has already been done.

There are federal laws preventing the Census Bureau from releasing personal information in a way that can be traced back to the individual. It is illegal for census information to be used against people. It also prevents the Census Bureau from sharing statistical information with other federal agencies — like immigration enforcement agencies — for nonstatistical purposes.

“Ultimately, this is a question of standing up to be counted to make sure that people receive the full amount of political power that they in their communities deserve, and to make sure that they receive the kind of resources their community deserves,” said Thomas Wolf, counsel for the Democracy Program at Brennan Center for Justice.

About the data: The “hard to count” dataset was provided by The Associated Press. We limited our analysis to areas with 50 census tracts or more. A census tract is a small section of a county that includes, on average, about 4,000 people.

The Associated Press contributed to this story.

Disha Raychaudhuri may be reached at disha@njadvancemedia.com. Follow her on Twitter @Disha_RC.