The US Supreme Court appears likely to allow the Department of Commerce to reinstate a citizenship question on the 2020 Census. This is largely viewed as a political controversy at the moment. The inclusion of a citizenship question has proven to dampen response rates among non-citizens, who tend to be people of color. The result will be gains in representation for Republicans at the expense of Democrats (political district lines are redrawn every 10 years as a result of the Census). Federal funding will likely decrease for states with large immigrant populations.

It should be noted that the Census bureau itself has come out against this change, arguing that it will result in an undercount of about 6.5 million people. Yet, the administration has pressed forward and has not committed funds needed by the Census Bureau to fully research the implications. The concern isn’t just about non-response from non-citizens. In tests done by the Census Bureau, non-citizens are also more likely to inaccurately respond to this question than citizens, meaning the resulting data will be inaccurate.

Clearly this is a hot-button political issue. However, there is not much talk of how this change may affect research. Census data are used to calibrate most research studies in the US, including academic research, social surveys, and consumer market research. Changes to the Census may have profound effects on data quality.

The Census serves as a hidden backbone for most research studies whether researchers or clients realize it or not. Census information helps us make our data representative. In a business climate that is becoming more and more data-driven the implications of an inaccurate Census are potentially dire.

We should be primarily concerned that the Census is accurate regardless of the political implications. Adding questions that temper response will not help accuracy. Errors in the Census have a tendency to become magnified in research. For example, in new product research it is common to project study data from about a thousand respondents to a universe of millions of potential consumers. Even a small error in the Census numbers can lead businesses to make erroneous investments. These errors create inefficiencies that reverberate throughout the economy. Political concerns aside, US businesses undoubtably suffer from a flawed Census. Marketing becomes less efficient.

All is not lost though. We can make a strong case that there are better, less costly ways to conduct the Census. Methodologists have long suggested that a sampling approach would be more accurate than the current attempt at enumeration. This may never happen for the decennial Census because the Census methodology is encoded in the US Constitution and it might take an amendment to change it.

So, what will happen if this change is made? I suspect that market research firms will switch to using data that come from the Census’ survey programs, such as the American Community Survey (ACS). Researchers will rely less on the actual decennial census. In fact, many research firms already use the ACS rather than the decennial census (and the ACS currently contains the citizenship question).

The Census bureau will find ways to correct for resulting error, and to be honest, this may not be too difficult from a methodological standpoint. Business will adjust because there will be economic benefits to learning how to deal with a flawed Census, but in the end, this change will take some time for the research industry to address. Figuring things like this out is what good researchers do. While it is unfortunate that this change looks likely to be made, its implications are likely more consequential politically than it will be to the research field.