(Taken from the CUNY HTC Map Website)
What is the "hard to count" population?
The goal of the decennial census is to count each person in the United States based on their residence as of April 1. For the 2020 census, each household in the U.S. will either receive mailed instructions on how to fill out the census questionnaire online, or they will receive the actual questionnaire. The Census Bureau asks that as many households as possible submit their responses to this questionnaire via the Internet or by mail - this is the self-response component of the decennial census.
In prior censuses, the self-response rate in many parts of the country has been relatively high. But in other parts of the country and for some population groups more than others, the self-response rate has been relatively low. Households may not have submitted their census questionnaire for various reasons, such as having language difficulties, concerns about trust in government, or otherwise.
These areas and population groups are considered "hard to count" because the Census Bureau sends enumerators into the field to talk with each non-responding household one-by-one. This "non-response follow-up" component of the census can be difficult, time-consuming, & costly (to the Bureau, and to taxpayers). And if these groups and their communities are not counted fairly & accurately, they will be deprived of equal political representation and vital public and private resources.
Defining hard-to-count (HTC)
A census tract is considered hard-to-count (HTC) if its self-response rate in the 2010 decennial census was 73% or less. If 73% or fewer of the tract's households that received a census questionnaire mailed it back to the Census Bureau, it is determined to be a hard-to-count tract.