Home > Data Services > Catalog . Restricted Data . Census . ACS

Search Data Services

Meta Search
search across all the following databases:

Data Catalog
Data and documentation

Common questions and answers.

Entire collection of data resources.

Latest Data News

RSS Feed icon

Sage Stats and CQ Political Stats Trial

Breaking News: Protect the 2020 Census

The Fastest Growing US Cities Are Mostly In the West

Another rule from NIH: Demographers might get to ignore this one

Research on Health Disparities: Incarceration Matters

Data Services Knowledge Base


I am unsure how to merge geographic data to a file that I have. I noticed that the census tract numbers do not stand alone in the data file that I downloaded from the census and that the GEO variable is saved as a text variable so I am unable to merge my data sets using that variable.

Would you be willing to show me how to link these two data sets if all I have is the census tract number?


Census tract numbers are only unique within a county. You need to create a unique id based on state, county, and census tract.

Thus, the following:

st   county  tract
26   113     60202

can be combined into a unique id:


This is done via this algorithm:

id = (st*1000000000) + (county*1000000) + tract;  

In your data, you may only have the census tract, but ideally you know the state and county as well. Otherwise, if your data are for a single county within a state, you can just use the tract portion of the GEO_ID2 variable. If you save the item as 'text' it is in fixed format with state in the first two columns, county in the next three columns, and tract in the last 6 columns. Thus, you could read:

input junk 1-5 and tract as 6-11;

Related Question Groups: