Publication Date



This report summarizes the 2009 estimates results from the UMass Donahue Institute’s Population

Estimates Program (UMDI-PEP). These population estimates are developed in tandem with the

Donahue Institute’s data collection efforts, namely our group quarters and housing unit surveys.

There are several reasons why it is necessary for the Commonwealth of Massachusetts to develop its own population estimates. First, county and sub-county population estimates are a key resource for state and local governments, non-profits, and the private sector which use these estimates to prepare reports, grant applications, business plans, and state and federal compliance documents. At present, public agencies in Massachusetts develop their own estimates on a purely ad-hoc basis or rely upon somewhat questionable estimates from the U.S. Census Bureau that have not been vetted by experts that understand the local demography of the Commonwealth. Secondly, the process of generating population estimates helps UMDI evaluate the quality of the information collected through our surveys. Our population estimates provide an early look at how the new survey data will affect official

Census estimates and help us prioritize communities that are the best candidates for challenging official Census estimates. Lacking such checks, the Census Bureau has been prone to undercount the Massachusetts population. In 2008 alone, Donahue Institute supported challenges added population that could translate into between $3.2 and $33.09 million of federal resources.1 Lastly, developing our own estimates helps to identify the forces driving population change, whether through changes in migration, births, or deaths. Armed with this knowledge, state and local policymakers can address the policy challenges posed by demographic change in a more informed and proactive manner.

We estimate the 2009 population of the Commonwealth of Massachusetts at 6.64 million persons—a 4.4% increase from the last decennial census in 2000. This is 51,873 more persons than estimated by the U.S. Census Bureau for 2009. Much of this gain is a direct consequence of UMDI-PEP’s group quarters (GQ) and housing unit review (HUR) efforts. For the Group Quarters Review project, UMDIPEP collects and submits to the U.S. Census Bureau updated resident counts for GQ facilities. For HUR, the program collects and reviews building permits, mobile home placements and housing unit loss data for each town and city in Massachusetts to estimate the housing stock in the state and counties. The Bureau does not collect housing unit loss data directly from the towns (as it does with the building permits); instead it calculates a loss-by-age-of-structure rate for the U.S. as a whole and then applies this rate to all regions. New England's housing stock is much older than the national average, so this national rate does not correctly reflect the situation in the region. In 2009, we found that the Census Bureau had overestimated the demolitions and therefore underestimated the number of housing units and population for some towns and cities in Massachusetts. Also, some municipalities in the state have actually increased their housing stock due to “adaptive reuse” of older buildings, which was also a component that the Census Bureau routinely missed.

The Census Bureau’s official population estimates for 2009 incorporate data collected by the Donahue Institute on housing units, and may lead to revisions in their official estimates for past years.