The Three Pillars of Census Based Data

When most people hear the words "Census Bureau" they only think of one thing - "the" census. Of course what they really mean is the "decennial" census, being that survey we all take once every 10 years as part of our constitutional duties. In reality the Census Bureau conducts a slew of surveys covering a wide range of topics. However, there are three that are interrelated that I want to review here. Because they are often confused with one another, it is important to understand how they differ and what that difference means for the data user.

The first is the data product mentioned above - the decennial census. The decennial census is conducted once every 10 years, administered officially on April 1 of any year ending in a zero. Historically the decennial census has been used to capture not just population counts but also to help flesh out the character of the people living in the country. It did this by offering two forms - a short form and a long form.

The long form of the decennial census was sent out to approximately one out of every seven households during the survey period. This is the form that gave us all the "meat and potatoes" types of data used in grants and planning. The long form of the survey covered everything from levels of education, to poverty, to the number of vehicles in a household.

The rest of the country got the "short form" of the decennial census. It truly was short - it typically covered only 7 or 8 questions ! these were the most basic data collected, such as sex, race, age, etc., of people living in a household.This is the data that is most relevant to the Constitutional basis for conducting the census, namely for redistricting purposes.

So the decennial census used to have two formats (the long and short versions) and be done once every 10 years.