The value of property securing a debt is a very significant issue in determining how a creditor will be treated in a bankruptcy. Too much value above the debt and you may be adequately protected and prevented for getting Relief from Stay. Too little value and you may be deemed unsecured for significant amount of the debt.
Value in most cases but not all is based on an educated guess called an appraisal. In a narrow type of case the value is based on a market report.