HEADWATERS ECONOMICS GEOGRAPHIC DATA LIBRARY DOCUMENTATION

TITLE: 
Dataset Name: 		US Census Population Projections
Dataset Type: 		ACCESS

GENERAL DESCRIPTION: 
County growth that were the result of sharing out the official state forecasts from the US Census based on recent trend data since 1990.

DATA SOURCE(S):  		US Census
Date of Original Source Data:	
State Projections were done in March 2004.  County projections were based on history through 2005, completed in 2006.

DATASET EXTENT:  		United states
 
TABLES CODES AND VALUES: 

ITEM		ITEM DESCRIPTION
fips		5 digit county fips 

DATA LINEAGE SUMMARY: 
The dataset was downloaded from the web at
http://www.census.gov/popest/estimates.php
http://www.census.gov/population/www/projections/popproj.html

Projections from the Census were only available at the state level so we projected the county data using trend forecasts that were then scaled up or down to match the official US Census state projections.  Here are the steps:

1) Project trend forecasts using OLS based on 1990 to 2005, projected out from 2006 to 2020.  Historical data were from Bureau of Economic Analysis Regional Economic Information System (REIS) through 2004 (see TBL_REIS.txt) and 2005 was from the US Census Estimates (see TBL_CensusEst.txt).
2) Calculate the ratio of:
    the official state projections from US Census
    to the sum of the projections for all counties in each state
    
3) Scale county forecasts up or down using ratio in 2) to force the sum of our county projections in a state to match the official US Census projection. 


DATA SOURCES CONTACT(S): 
Name: 		US Census
Address:		U.S. Census Bureau
			4700 Silver Hill Road
			Washington DC 20233
			
Phone:   		1-866-758-1060 or
			Population (General Information) - Staff (POP)  301 763-2422
Email:   		http://www.census.gov/contacts/www/contacts.html
Web site: 	  	http://www.census.gov/popest/estimates.php
          
HEADWATERS ECONOMICS CONTACT: 
Name:			Headwaters Economics Geographic Data Library
Abbr. Name:		HEGDL
Address:		Headwaters Economics
                       	Mail: P.O. Box 7059, 
				Bozeman MT 59771 
                        
Web site:		http://www.headwaterseconomics.org
Contact Person:  	Jeff van den Noort
Phone:   		(406)599-1653
Email:   		jeff at headwaterseconomics.org