Which process involves comparing two sales that are identical except for one differing item?

Paired sales is the process that specifically involves comparing two sales transactions that are similar in every aspect except for one differing item. This method is particularly useful in real estate and property appraisal because it isolates the effect of that single variable on the value of the property.

By analyzing how the differing item impacts the overall sale price, appraisers can gain a clearer understanding of how specific features or conditions affect property values. This method helps in making more precise adjustments when determining the value of a property, ensuring that the analysis is based on empirical evidence from actual sales.

Other options like matched sales or comparative sales analysis do not emphasize the singular aspect of comparison as effectively as paired sales does, making the latter the most appropriate choice for the given question. Single variable analysis is more generalized and does not necessarily pertain to sales transactions specifically.