Estimated Population of Michigan Counties: 2000-2007 (pdf file)
Estimated Population of Michigan Counties: 2000-2007 (xls.file)

Estimated Population of Michigan Regions: 2000-2007 (pdf file)
Estimated Population of Michigan Regions: 2000-2007 (xls.file)

Components of Population Change: Vital Statistics, 2000-2007 (pdf file)
Components of Population Change: Vital Statistics, 2000-2007 (xls file)

Components of Population Change: Migration, 2000-2007 (pdf file)
Components of Population Change: Migration, 2000-2007 (xls file)

Impact of Methodological Revisions: Counties (pdf file)
Impact of Methodological Revisions: Counties (xls file)

Impact of Methodological Revisions: Regions (pdf file)
Impact of Methodological Revisions: Regions (xls file)

Description of Methodological Changes

Due to several methodological changes, the new estimates for 2006 and prior years to differ from estimates that have been released previously.

(1) Estimates of county-to-county migration are now based primarily on a comparison of addresses on federal tax forms filed in the two most recent years for each tax filer and dependent.  In prior years, migration was estimated on a household basis using address changes for the principal tax filer.  The new approach captures more movement of young adults who leave their family home to attend college, join the military, start a  household, etc.  This tends to increase the estimated population of central metropolitan counties and counties with colleges or military bases.  It tends to decrease the population of other counties.

(2) The Census Bureau has determined that previous estimates of international immigration were too high.  Improving this aspect of the methodology reduced population estimates throughout the nation, but the largest reductions tended to occur in large cities and in states that attract a large number of foreign immigrants.

(3) Several communities around the nation, including Detroit, filed challenges to their population estimates for 2006.  The Census Bureau accepted these challenges.  This increased the new 2006 population estimates for Detroit, Wayne County, and the state of Michigan by nearly 50,000 people.  However, the population estimates for Michigan and for Michigan communities other than Detroit were also reduced by 30,000 people to compensate for estimate challenges from other states.  The estimated population change from 2006 to 2007 was not affected.

Each of the three methodological issues discussed above has a different effect upon Michigan's estimated population.  The first change reduces the state's population and its share of the nation's population, since the number of people who leave Michigan to attend college or join the military is larger than the number of students and military personnel who come to Michigan from other states.  The second change also reduces the state's population, but it increases its share of the nation's population because the reductions were greater in many other states.  The third change increases Michigan's population and its share of the nation's population. 

The net effect of all the methodological changes was to increase Michigan's estimated population for 2006 by  6,700 people and to increase its share of the nation's population from 3.37% to 3.38%.

Updated 3/20/08