Niece to daughter in 10 years

[lostinspace]

I have found an 1881 census listing for an ancestor who is at age 3 the daughter of the head of the household. 10 years later, she is listed as his niece.

There's no doubt in my mind it's the same people- ages, places of birth and occupations all match- and the head's job is as a police constable, so I wouldn't have thought it's just a mistake he made.

Had it been the other way round, I'd have presumed adoption.

Any guidance or thoughts?
Thanks in advance..........