Coefficient of deviation
A state measure of assessment uniformity showing how tightly individual assessment-to-sale ratios cluster around the municipality's average.
New Jersey example
A lower coefficient generally indicates a more uniform assessment roll; it does not prove one parcel is correctly assessed.
Official source
https://www.nj.gov/treasury/taxation/lpt/localtax.shtml
This is a plain-English summary. Rules and dollar amounts change, so check the official source or a professional before you file or sign anything.