A test of reasonableness is applied to a [glossary:granny flat:52] [glossary:entry contribution:426]. The premise behind the reasonableness test is that in some circumstances the value of a lifetime accommodation interest may exceed the value of the [glossary:principal home:349] being transferred. The reasonableness test uses an approximation of actuarial values, based on [glossary:life expectancy:348], to estimate the value to the person of the life accommodation interest.