Which method of measuring depreciation assumes that depreciation is straight-line?

The method that assumes straight-line depreciation is the Overall Age-Life approach. This method evaluates depreciation based on the age of the property compared to its expected lifespan. Under this method, it is assumed that the value of the property decreases evenly over time, distributing the loss in value uniformly throughout its economic life. This aligns perfectly with the straight-line depreciation concept, where an asset loses value at a constant rate.

In contrast, while the Engineering Breakdown approach might involve estimating depreciation by dissecting different components of a property and assessing their individual deterioration, it does not inherently simplify to a straight-line calculation. Similarly, the Sales Comparison approach relies on comparing similar properties to ascertain value and does not inherently involve a depreciation measure. Meanwhile, the Capitalization of Rent Loss would focus on evaluating potential income loss rather than the physical depreciation of the property itself. Thus, Overall Age-Life is the most fitting option, as it directly correlates with the notion of straight-line depreciation.