One sale says little about the overall assessment. Conversely, when many sales of the same property type are reviewed in unison, it does establish certain trends and patterns that become meaningful. One such measure is the assessment level that is indicated by computing the central tendency of all sales ratios that comprise the study sample. This central point in the study is the middle ratio when all the ratios are arrayed.
For example, if a study sample has the following ratios: 86%, 90%, 92%, 95%, 97%, 98% and 99%, the assessment level is the median ratio of 95%