I’m working with ACS data (1-year samples) from 2014-17. I’ve found a handful of observations in each year (<30) for which the serial number group does not have a household head (related=101) or a first person (pernum=1). Shouldn’t every unique household (grouped by year datanum serial) have one household head/first person? For these observations, the “related” variable is across the board, including spouse, child, partner/friend/visitor, etc. Does this seem correct?