MARBASECIDP 2016 and 2017 match rate?

I’ve been using MARBASECIDP to match IPUMS CPS ASEC and basic monthly records. For years prior to 2016, all or nearly all records in the monthly have a match in ASEC. However for 2016 and 2017, over 6% of monthly records do not appear to have a match in ASEC. Did something change in 2016?

thanks

Yes, there was a small change in the 2016 and 2017 ASEC sample design. Specifically, these samples included a split-sample design intended to test new questions regarding health insurance and income. This results in some March basic monthly households not being included in the ASEC sample. A match rate of around 93% is what we expect in these years.

Thanks, that’s a load off my mind.