What evidence do I need to present to the Board of Assessors?
State law puts the burden of proof on the property owner to show that the assessment is incorrect. Stating that the property taxes are too high is not relevant. You should establish on the application what you think your property is worth.
The best evidence that could be considered would be a recent sale price of your property. The next best evidence would be recent sales of properties that are similar to yours. The closer in similarity and proximity, the better the evidence.
Another type of evidence that could be considered would be a recent appraisal of your property.