First off, thanks to the ACS folks for releasing today's documentation on next week's ACS release; it's very helpful to have this information in advance.
I wanted to bring people's attention to changes to tables on health insurance by age: B18135, B27001, B27002, B27003, B27010, C27001A-I, C27004, C27005, C27006, C27007, C27008, C27009, C27016, C27017, and C27018.
The age ranges for these tables have changed; for example, in B27001, instead of ages 6 to 17, it's now 6 to 18; 18 to 24 is now 19 to 25, etc. (Starting at age 35, the definitions are unchanged.)
Although I understand that there's rationale for updating the indicators to "categories that better align with the current health insurance landscape", this creates a significant problem for comparing to previous years' data. Since these indicators were first introduced in the 2008-2012 ACS, this release would have marked the first instance where estimates could be compared with a non-overlapping ACS year. However, these have now changed definition in such a way that they're not comparable. This primarily affects statistics on children.
It would have been useful to release the new age definitions as a different table, to maintain comparability. Anyone who was planning on using previous years' documentation for this year's data should be aware of this change. And to be clear, the Census was upfront today about this change, including it in their list of table and geography changes.