The question is asked to owners. Renters are asked how much they actually paid in rent. The main reason why owners are asked for their estimate is because owner

The question is asked to owners. Renters are asked how much they actually paid in rent. The main reason why owners are asked for their estimate is because owner-occupied houses can be systematically different (probably more expensive/higher class) than renter-occpied houses, so estimating owner-occupoed rents with actual rents can be biased.