Whether it’s an on-line quiz, a $300 chromosome test or an $800 blood panel, a lot of people seem to be interested in whether they’re aging faster or slower than their chronological age would suggest.

Unfortunately, they’re just going to have to wait and see.

A head-to-head comparison of 11 different measures of aging, including blood and chromosome tests like those being sold commercially, has found that they don’t agree with one another on how fast a given person is growing older.

This comparison is based on a life-long study of nearly 1,000 people in Dunedin, New Zealand who have been studied extensively from birth to age 38.