Market transparency determines the relative usefulness of different types of data. The application, veracity and appropriateness of comparable data are not universal.
Property valuation is deceptively complex; its appearance of simplicity belies the requisite skills and knowledge of the valuer for understanding the property market. As I wrote previously, comparison is the linchpin of all real estate valuations and is more than the simple use of transactional comparables but relies upon a plethora of other signposts that enable the valuer to gauge the market. The choice of signposts is dictated by data availability: different markets, of different economic transparency, will rely upon different data.
In a transparent market, the best data may indeed be a recent sale, whereas in a more opaque market asking-price information may be the chosen anchor for the valuation. Normally, the distinction between market types strongly reflects geographical or cultural differences, but the impact of Covid-19 has meant that the availability of data across transparent and opaque markets has been much more uniform internationally. All markets have seen stagnation in transactions, and so all valuers have had to look to other signposts to help them assess market value.
In any market, though, no good valuer would simply replicate the numbers from comparable sales and other data without further analysis. It may be that the market is static and thus prices will not have changed, or the market may be falling or rising. All valuations need to be placed in an economic context. Comparable evidence is the starting point but not the sole contribution; the valuer must assess what data is available to make a professional judgment as to price in the market today.
Valuation is a heuristic process that relies upon the expertise of the valuer. There may be systems and models to aid the valuer, but the crux of the process is interpretation of the market inputs that ultimately provide the valuer with their opinion of market value. Comparable evidence is part of this process, but without the expert judgment of someone who understands the nuances of the data, a valuation based solely on raw numbers could be erroneous.