The four major trade groups representing the U.S. marketing industry are pushing back against the Trump Administration’s proposal to add a question regarding citizenship to the 2020 Census.

An August 7 memo sent to the Commerce Department — which was jointly signed by the CEOs of the Association of National Advertisers, the American Advertising Federation, the American Association of Advertising Agencies and the Advertising Research Foundation — laid out these groups’ criticisms of the proposed plan, which they believe could harm the decennial procedure’s data, which allocates both federal funds as well as seats of the U.S. House of Representatives based on states’ populations.

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“We are concerned that the addition of a citizenship question would depress response among both citizens and their families (even if family members are indeed citizens),” the letter read, in part. “That runs the risk of non-respondent bias by significantly undercounting immigrant, minority, and low-income populations. If immigrants and others avoid the national head-count, the census results will be flawed.”

The Trump’s administration’s plan presents a challenge to the marketing world, whose continuous research efforts could be damaged as a result of potentially flawed U.S. population data that many believe would result from this decision.

“Since the census is the foundation for population estimates that support the marketing industry, inaccurate census data would lead to misallocated marketing resources,” which could have “particularly negative impact on media that server multicultural marketers,” the letter continues.

The Trump administration in late March announced that it plans to include a question in the 2020 Census regarding how many of a household’s members are U.S. citizens. The U.S. Justice Department said that data is critical for its enforcement of the Voting Rights Act, which is designed to prevent discriminatory voting practices.

The announcement was met with immediate pushback from civil rights groups such as the Urban League and the ACLU, among other critics who said the decision would instill fear in immigrant communities and could potentially deter people from participating in the census, resulting in an underrepresentation of both the national population as well as citizens’ representation in Congress in areas with large minority and immigrant populations.

Several states have since filed lawsuits, alleging the proposal violates the U.S. Constitution and federal laws. Questions regarding U.S. citizenship have appeared in censuses throughout the ages, the last time appearing in 1950.

The Commerce Department, which oversees the Census Bureau, had until yesterday been soliciting public comments on the controversial addition in preparation for the upcoming count.

The Association of National Advertisers in July retained D.C.-based legal and lobbying firm Venable to advocate on Capitol Hill on data protection and data security issues, among other matters.