Is it wrong to take the measurement of skinfold with the clothes on?
Taking skinfold measurements with clothes on does affect you accuracy and reliability, so it is not an ideal way to do the test. However, sometimes you have to do such measurements when it is appropriate for a modest client. If you have no choice but to take the measurement through clothes, you can take a measurement of the thickness of the clothes using the calipers, then subtract that from your skinfold measure.