Jeff Zalesin at Yale Law Journal Forum. Abstract:

The Constitution requires legislative redistricting plans to have approximately equal populations in each district. But no one knows exactly how many people live in any district, because census data are never fully accurate. Courts have developed little doctrine in response to this problem. Yet, the need for such doctrine is growing. Policymakers have largely given up on improving the census through statistical adjustment. The 2020 Census will likely be less accurate than its predecessors, thanks to political interference and the COVID-19 pandemic.

This Essay offers a pragmatic approach to litigating malapportionment cases with imperfect population data. Courts in malapportionment litigation should clarify that they will consider evidence that the data underlying a redistricting plan are biased, such that the district populations are less equal than they appear. Such evidence will be especially important when courts evaluate maps drawn with novel types of data, such as estimates of citizen voting-age population.