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

Search Data Services

Meta Search
search across all the following databases:

Data Catalog
Data and documentation

KnowledgeBase
Common questions and answers.

Resources
Entire collection of data resources.


Latest Data News

RSS Feed icon

Expansion of Free Lunch Could Have a Negative Effect on Research Data

You’ll live longer than you think you will [HRS data]

Federal Register Notice: Some ACS questions on the chopping block

Political Science: A self-inflicted wound?

Sage Stats and CQ Political Stats Trial

Data Services Knowledge Base

Q:  

I am using data from the American Community Survey (ACS) for Monroe and Lenawee counties in Michigan. The tables from American Factfinder have margins of error for all the cells. However, if I am combining the two counties is there a way to calculate new margins of error based on this larger population?

A:  

The best description of the way to do this is in this technical appendix:

Understanding and Using ACS Single-Year and Multiyear Estimates

Appendix 3 has several examples of computing margins of error when one is combining geographies (counties, census tracts, etc.).

Annotated Resources:

Direct Links:

Related Question Groups: