4.1.2. Market Value: The Measure of Just Compensation.To ensure a fair, objective and practical standard, federal courts have long held that market value is normally the measure of just compensation.173 The market value measure “has an external validity which makes it a fair measure of public obligation to compensate the loss incurred by an owner as a result of the taking of his property for public use.”174 The “appraiser’s function is to assist…in [the] determination of just compensation by furnishing an opinion of market value.”175 Opinions of market value for federal acquisition purposes must follow federal law to provide a fair measure of just compensation. Otherwise, “a finding on the value of a [property interest] that ‘is derived from the application of an improper legal standard to the facts’ must be remanded for new factual findings for application of the correct legal standard.”176