The simple premise of property tax assessments is that a property is to be valued at its market value.  What would its value be in a sale between a willing buyer and a willing seller? MPAC uses mass appraisal techniques, which often miss local market factors.

This building below - is it located in a large city, or a small one?  Or maybe a rural area?  Is it zoned for redevelopment?  Is there a nearby factory with a major contamination issue? How are nearby similar properties selling? All of these questions should affect the assessment.