Population measures provide insight on the changing size and face of communities. The racial and ethnic composition of a community can offer insight into its levels of diversity, which can bring with it challenges and opportunities.

MetroWest has grown more diverse since 2008-12. Its Asian population grew fastest, gaining 46%, while the African American population increased 25%, and Hispanic residents grew 43%. The white population was largely stable and still makes up a large majority, with 2,353,600 residents. The White majority has fallen from 81% of the population in 2008-12 to 75% in 2018-22.

Massachusetts experienced similar changes, but compared to MetroWest, it had smaller increases in its Asian, African American, and Hispanic populations (36%, 12% and 39%, respectively). Racial and ethnic minority populations also increased at the national level, but at a slower pace than either MetroWest or Massachusetts.

White residents were the largest racial group in every municipality in MetroWest in 2018-22, but some localities experienced large increases in other racial groups since 2008-12. Of the areas with samples large enough for statistically reliable measurements, the largest Asian population increases were in Westford, at 130%, and Natick, at 111%. Lexington, Westborough and Needham follow, with 67%, 58%, and 58% increases in their Asian populations since 2008-12. Waltham has the largest percentage increase of African Americans, at 45% of its population. Overall, Marlborough, at 72%, has the highest percentage increase of Hispanic residents, followed by Framingham and Milford, at 38% and 33%, respectively.

The composition of the U.S. population is becoming more racially and ethnically diverse as people of color grow in representation and will be a majority within the next two decades. Latino, Asian and multiracial groups are experiencing the largest growth with Latino's rapid increase caused largely by immigration. Latino immigrants who enter the U.S. tend to be younger and of child-bearing age. Latinas in the U.S. have higher fertility rates than Black and white women. Black, Latino and multiracial populations are also experiencing higher rates of births relative to deaths, while whites are experiencing the opposite.

Rate is percentage change from 2000. The multiyear figures are from the Census Bureau's American Community Survey. The bureau combined 5 years of responses to the survey to provide estimates for smaller geographic areas and increase the precision of its estimates. However, because the information came from a survey, the samples responding to the survey were not always large enough to produce reliable results, especially in small geographic areas. CGR has noted on data tables the estimates with relatively large margins of error. Estimates with three asterisks have the largest margins, plus or minus 50% or more of the estimate. Two asterisks mean plus or minus 35%-50%, and one asterisk means plus or minus 20%-35%. For all estimates, the confidence level is 90%, meaning there is 90% probability the true value (if the whole population were surveyed) would be within the margin of error (or confidence interval). The survey provides data on characteristics of the population that used to be collected only during the decennial census.

The Census Bureau asks people to identify their race (white, African-American, etc.) separate from their ethnicity (Hispanic or non-Hispanic). So the totals for these categories cannot be added together, as people show up in both a racial and ethnic group. Data for this indicator are released annually in December.