in many areas the most usable part of tax info is the unexempt amount of taxes and the legal description. unless you fully know the tax appraisal system in the area you are researching the property valuation is only confusing and has no translation to market value of any kind. some areas report only filed mortgage amounts, or they may have frozen appreciation due to age of current owner. use the tax info for concrete info only, not valuation.
The tax records are excellent tools. With that being said, most of them are wrong which is why there so useful. Atleast in my area I’ve yet to see an assessed value that was anything but 20% below market value. Sometimes this may not be true so know your area well. This is a great leveraging tool to lower the price.
However, disregard the sq. footage if listed being that tax assessors can’t measure anything right. There assessed value is typically derived from a quick drive-by or even without looking at the property.
When looking at the transaction price, make sure it says something like arms-length, meaning the buyer and seller weren’t friends or relatives or whatever.