I heard similar stories about the census.
In particular, they would find situations like father apparently being younger than son. You could just discard such data, but maybe you should guess what they meant - did they transpose digits in the date of birth? Did they just get confused being “your relation to person A” and “person A’s relation to you”? So they have lots of data cleaning to fix those errors .
But great care was needed to make sure that it didn’t wrongly “correct” rare but possible situations - like housemates who just happen to share the same surname, or couples with a large age difference, and so on.
Biting the hand that feeds IT
