Using ZIP Code Level Data in the COI

Published: 01.08.2022 Updated: 01.08.2022

The Child Opportunity Index (COI) 2.0 ZIP code data are ZIP code level estimates of neighborhood opportunity derived from 2015 COI 2.0 census tract data. We created ZIP code level COI 2.0 estimates for data users who – for different reasons – cannot work with census tract COI data. Our method for aggregating census tract to ZIP code data uses weights published by the U.S. Department for Housing and Urban Development. Please refer to the COI 2.0 ZIP code data technical documentation available on this page for more detailed information on the differences between using COI 2.0 and COI 2.0 ZIP code data. COI 2.0 ZIP code data can be downloaded here. For more information on the census tract COI 2.0 data on which ZIP code data is based, please review the COI 2.0 technical document and database.

Frequently Asked Questions

When was the COI 2.0 ZIP code data measured?

It is important to note that for all ZIP code COI 2.0 data files, neighborhood conditions were measured in and around 2015. The years in the data file titles DO NOT denote the years in which neighborhood conditions were measured but refer to the ZIP code definitions for a given year. ZIP code definitions are continually updated by USPS, for example, to incorporate newly constructed buildings/addresses. As a result, the weights used to calculate ZIP code level COI 2.0 data change continually, too. We, therefore, publish multiple ZIP code data files based on 2015 COI 2.0 census tract data that correspond to the ZIP code definitions in a given year.

How do I choose the right COI 2.0 ZIP code data file for my project?

You should try to match the file to the years in which the ZIP codes in your data were collected. For example, the file “COI 2.0 ZIP code data for 2020 ZIP codes” contains 2015 COI 2.0 data aggregated to ZIP codes as they were defined in 2020. We would recommend users to use this file if their goal is to link it to another dataset with ZIP code data collected in 2020. Or, if ZIP code data was collected in 2017, we recommend to use the “COI 2.0 ZIP code data for 2017 ZIP codes” file.

What if my data span many years?

If ZIP code data was collected over multiple years, we have created ZIP code estimates that average over ZIP code definitions for multiple years. Please contact us here to request access to these data.

Clemens Noelke
Clemens Noelke
Research Director
Headshot of Robert Ressler
Robert Ressler
Senior Research Associate
Nancy McArdle
Nancy McArdle
Senior Research Analyst