Since it's talking about savings I would assume it means highly liquid assets I would assume a house wouldn't be liquid enough to use in the survey just stuff like how much money you have saved.
Worth - mortgage principle = savings.
I can think of one reasonable instance in which home equity may have equivalent liquidity as a savings account: when filing for bankruptcy.
Not for this survey though. It looks like it is purely about money in a savings account, which is a pretty poor measure.