Which formula is NOT one of the methods for developing an effective tax rate?

The cost approach is not typically recognized as one of the standard methods for developing an effective tax rate. Effective tax rates are generally derived from approaches that more directly relate to the income potential of a property or its market value.

The effective tax rate is often calculated using methods that encompass the earnings potential and comparative market assessments. The EAT formula, market comparison, and income method all focus on evaluating properties based on how they perform in the market or their ability to generate income, which are essential considerations for taxable value assessments.

In contrast, the cost approach primarily involves estimating the value based on the cost to replace or reproduce the property, minus depreciation. While valuable in certain appraisal contexts, it does not provide the necessary information relevant to calculating a tax rate, making it an unsuitable method for this particular purpose.