What measures the extent of undervaluation in property assessments?

The correct choice, which focuses on the magnitude of deficiency, directly relates to how property assessments can fall below their actual market value. This measure indicates the extent to which assessed values are lower than the true value of properties, reflecting potential issues in assessment practices or market valuation.

Understanding the magnitude of deficiency is crucial for assessing the equity of the assessment process. If properties are commonly undervalued, it may lead to disproportionate tax burdens and can impact the overall revenue for local governments. By measuring this deficiency, appraisers can identify trends, disparities, and possible areas that need adjustment to ensure that assessments are fair and accurate.

The other choices, while relevant in the context of property assessments, focus on different aspects. Uniformity within a class of property addresses how consistently properties in the same category are assessed, rather than the extent of undervaluation. The average level of assessment measures the overall ratio of assessed values to market values but does not specifically indicate how much particular properties are undervalued. Field review frequency pertains to how often properties are physically inspected and does not directly relate to measuring undervaluation. Hence, the magnitude of deficiency stands out as the most relevant measure in the context of assessing the extent of undervaluation in property assessments.