Montana County & Reservation Profiles
American Community Survey (ACS) 5-year Estimates
(Released December 2015)
ACS Data Set Comparability – As a general rule of thumb, 1-year ACS estimates can be compared to other 1-year estimates. Different year estimates (i.e. 3-year and 5-year) should NOT be compared to one another because the time span represented by each estimate differs (i.e. 1 year versus 3 years versus 5 years of data).
Multi-year estimates should not be compared to like multi-year estimates that include the same year within both datasets because they are not unique samples. For example, the 2010-2014 5-year estimates should not be compared to the 2009-2013 5-year estimates since data from 2010, 2011, 2012, and 2013 are included in both estimates and, therefore, are not exclusively comparable. Essentially, 80% of each respective data set is estimated using exactly the same data.
(Released December 2014)