See: Net Debt to Assessed Valuation.
It's really close to being the same thing. Assessed or estimated are close terms. When something is assessed, a professional valuation expert has presumably taken off the blindfolds when they threw the dart at the donkey tail, trying to figure out what Company X was worth. But in an estimated valuation, the blindfolds stay on, more or less.
See: Net Debt as well, just because we need the clicks. Thanks.