Which approach involves data collection and the analysis of market data to develop units of comparison?

The Sales Comparison Approach is centered around the principle of substitution, which states that a property's value can be determined by looking at the sale prices of similar properties in the market. This approach involves gathering data on comparable properties that have recently sold, including their characteristics, conditions, and locations. By analyzing this market data, the assessor can develop units of comparison, such as price per square foot or price per unit, which helps in estimating the value of the subject property.

In contrast, the Cost Approach estimates value based on the cost to replace or reproduce the property, minus any depreciation. The Income Approach focuses on the income-generating potential of the property and calculates value based on expected future cash flows. Economic Base Analysis is a broader concept that examines the economic activities of a region in relation to property values but does not specifically involve market data comparison. Since the Sales Comparison Approach relies specifically on the collection and analysis of market data to establish value through comparisons, it is the correct answer.