There are many folks awaiting the results of the 2010 Census. Researchers and demographers especially will feast on detailed data releases that begin in December and go right through to 2014 with statistics gleaned from over 130 million households.

Before the first results from the 2010 Census are available, the Census Bureau has several other releases between September and December that will describe the U.S. population.

It’s important to know how they’re different so you don’t get confused.

In late September, we’ll release 2009 American Community Survey (ACS) 1-year estimates for areas with a population of 65,000 or more. These are NOT 2010 Census results; they are based on survey data collected in calendar year 2009. Like the ACS data released in previous years, these data describe the characteristics of the population (like education and socioeconomic status) and housing (like home values and vacancy rates). It’s important to remember that these data describe 2009, not 2010.

In early December, we will release the 2005-2009 ACS 5-year estimates. They’ll report the same type of characteristics as September’s release, just for smaller areas and for a 5-year time period. These are NOT 2010 Census results, but are based on survey data collected between January 2005 and December 2009. We will release these estimates for the smallest geographic areas including census tracts (units of about 4,000 people) and even smaller, block groups. With this first-ever release of these 5-year estimates and each year’s update to come, people will no longer have to wait a decade for the next look at detailed characteristics data for their small areas.

In December, we will release the 2010 demographic analysis estimates of national population by age, sex, and race (Black and nonblack). These are NOT 2010 Census results, but are estimates based on historical data on births and deaths and estimates of immigration and emigration. As such, these estimates are independent of the 2010 Census data collection efforts, so they give us a separate gauge of how big our population has become since the last portrait was taken in the previous census.

Finally, sometime before December 31, 2010, we will release state population counts – these ARE the 2010 Census results – the very first results we’ll all see.

This is the first census when we have many different data releases made public so close to the first release of Census data. Some experts fear that this will confuse the public, but I am optimistic that taken together, this can be a moment of education to help describe why we need multiple measures of our society over time, each with its own strengths.

The Census is a full count of our country taken every 10 years, at a snapshot in time. Its strength is that it can provide accurate data for very small areas and population groups. The ACS is a continuous sample survey. ACS does not count everyone but relies on a sample of us each year to help estimate how all of us are doing. Its strength is that it collects data on a wider variety of subjects and that it produces estimates each and every year. Demographic analysis does not rely on collecting information via a questionnaire or interview. Instead, it uses information from other sources—mostly vital statistics records. As such, its strength is providing an alternative method for estimating the total population of the country.

Together, all of these data help us better understand who we are, where we have come from, and how we are doing. Each in its own way is helpful to a greater understanding of our population.