Correction for weights change in 2006 for marital rates

USA
1

Hello,

My collaborator and I are working with ACS microdata from IPUMS USA and have noticed a discontinuity in age-specific marital-status estimates around 2005-2006.

Specifically, we are using MARST and PERWT to estimate the proportion married by year and age group. For our project, we need a consistent population counts of married versus unmarried by age. However, we see an odd bump around 2005 that appears to line up with the ACS change in weighting and estimation methodology described by the Census Bureau here:

My understanding is that the 2006 ACS introduced the family-equalization weighting change, and that this affected published marital-status estimates. What we have not been unclear about is whether this change affected some age groups more than others, or whether there is any recommended way to construct a more consistent age-specific married/unmarried series spanning the pre-2006 and post-2006 ACS.

So I wanted to ask:

  1. Does IPUMS have any guidance on using ACS MARST and PERWT to build consistent age-specific married/unmarried population estimates across the 2005-2006 break?
  2. Is there any public-use weight variable, adjustment, or recommended workaround for the 2002-2005 ACS that better approximates the post-2006 methodology?
  3. Has IPUMS encountered age-specific discontinuities in marital-status estimates around this change, or is the standard recommendation simply to treat 2005-2006 as a methodological break?

Any suggestions would be very helpful. Thank you in advance.

2

These changes to the weighting procedure for the ACS are also discussed in this Census Bureau working paper. Generally speaking, the ACS samples from 2000-2004 are considered a testing period with nationwide implementation of the ACS only occurring in 2005. Moreover, nationwide implementation revealed additional data inconsistencies that had to be addressed. The ACS underwent numerous methodological changes during this period that affect comparability; chapters four and five of this detailed history of the ACS cover some of these.

IPUMS does not have any guidance for bridging this change in the methodology. My recommendation is to review the relevant Census Bureau user notes and working papers for information on how earlier estimates changed when the 2006 methodology was applied. This should help give a sense of whether the changes are significant enough to warrant dropping the 2002-2005 samples from your analysis or if you prefer to retain them given this methodological break.

You could also use the Current Population Survey (CPS) as a benchmark for these years. While the CPS is produced primarily for analyses of the labor market, it includes demographic variables as well and is weighted to be representative the civilian non-institutionalized population (refer to CPS Technical Paper 77 for details on the weighting methodology). IPUMS provides access to harmonized CPS data through IPUMS CPS.