When a lower-quality property is adjacent to a higher-quality property, it can diminish the value...

The principle of regression states that a property of higher value may decrease in worth when located near or among lower-quality properties. Conversely, the principle of progression means a lower-valued property can gain value by proximity to higher-quality ones.

This concept is emphasized in the Maryland pre-licensing module “Real Estate Appraisal and Valuation” to explain how neighborhood characteristics influence market value.