(a) Definitions. The following words and terms, when used in this subchapter, shall have the following meanings, unless the context clearly indicates otherwise.
  (1) Appraisal--A statement that estimates the market value or other legally required value of property.
  (2) Appraisal ratio--The ratio of a property's appraised value as determined by the appraisal office or appraisal review board (the County Appraisal District (CAD)) value, as applicable to:
    (A) the sale price of the property; or
    (B) an independent appraisal of the property, as applicable.
  (3) Appraiser--A comptroller employee or contractor who conducts appraisals for the property value study.
  (4) Assigned value--The value of property determined in the property value study.
  (5) Coefficient of dispersion--The absolute average deviation of appraisal ratios in a sample from the median appraisal ratio for the sample, expressed as a percentage of the median.
  (6) Comptroller--The Comptroller of Public Accounts or the Comptroller of Public Accounts' designee.
  (7) Confirm--A sale is confirmed when the comptroller has documented that the sale price for a property is correct.
  (8) Documentary evidence--Writings such as letters, memoranda, appraisal records, or deeds.
  (9) Local property--Property other than utility, industrial, mineral, or 1-d or 1-d-1 qualified agricultural property.
  (10) Median appraisal ratio--The median level of appraisal is the median appraisal ratio of a sample of properties collected as part of the school district taxable value study in an appraisal district. The median appraisal ratio for a sample of properties is, in a numerically ordered list of the appraisal ratios for the properties:
    (A) if the sample contains an odd number of properties, the appraisal ratio above and below which there is an equal number of appraisal ratios in the list; or
    (B) if the sample contains an even number of properties, the average of the two consecutive appraisal ratios above and below which there is an equal number of appraisal ratios in the list.
  (11) Price related differential--The price related differential is the mean of a property sample divided by the weighted mean of that sample.
  (12) Property value study--The studies conducted by the comptroller in alternating or consecutive years pursuant to Government Code, §403.302 and Tax Code, §5.10, according to a coordinated schedule that ensures that CAD reviews required by Tax Code, §5.102 are conducted in years in which the studies of school districts within the CAD are not performed, except when consecutive year studies are mandated. The schedule of alternating studies and CAD reviews shall be determined by the comptroller.
  (13) Random sample--A sample in which each item of the population has an equal chance of being included.
  (14) Representative sample--Representative means composed of individual properties that collectively reflect the individual characteristics of the population from which they were drawn. A representative sample meets the requirements for operational representativeness set forth in the International Association of Assessing Officers' Standard on Ratio Studies.
  (15) Sale--A transfer of property for consideration.
  (16) Sale date--The date on which a deed or other document transferring title to real property by sale is executed.
  (17) Sample--A group of properties analyzed to determine characteristics of property in a school or appraisal district.
  (18) School district split--Each portion of a school district located in different counties where properties are appraised by different appraisal districts.
  (19) Stratification--Stratification divides the range of information for property in a district or property category into intervals and lists the number and CAD value of properties falling into each interval.
  (20) Stratified weighted mean appraisal ratio--A stratified weighted mean appraisal ratio is calculated by separating the properties in a category sample into subcategories by value range or other property characteristics (strata) and determining the weighted mean appraisal ratio for each of the strata. The value of property in each of the strata is calculated by dividing the total CAD value by the weighted mean appraisal ratio. These individual market value estimates are then added to produce a market value estimate for the total category sample. The total CAD value of property in the category is then divided by the total category market value estimate to produce the stratified weighted mean ratio.
  (21) Verify--A sale is verified when the comptroller has documented that a sale is a market value transaction as defined by Tax Code, §1.04(7).
  (22) Weighted mean appraisal ratio--The weighted mean appraisal ratio is a number calculated by dividing the total CAD value of property in a sample by the total of corresponding sale prices or appraised values of property in that sample.
(b) General statement of policy. The study constitutes a limited audit of the taxable value of property in the districts. The purpose of this section is to ensure that sufficient competent and relevant evidence affords a reasonable basis for the comptroller's judgments and conclusions regarding the taxable value of property in a school district and the appropriate measures of appraisal level and uniformity in an appraisal district.
(c) General standard. Except where inconsistent with these sections, the Standard on Ratio Studies, International Association of Assessing Officers, is adopted by reference as a standard for the conduct of the property value study. For the purposes of ratio study design, including but not limited to stratification and sampling design, the requirements to apply appropriate standard statistical analysis techniques set out in Tax Code, §5.10(a) and to use generally accepted auditing and sampling techniques set out in Government Code, §403.302(a) and (b) are met by complying with the Standard on Ratio Studies.
(d) Changing appraisal methods. The comptroller will consult regularly with representatives of property owners, industries, appraisal firms, and other interested parties to keep abreast of changing appraisal methods.
(e) Selection of property studied. The accuracy of the estimate of taxable property value for each school district in this state shall be the primary consideration in determining the amount and category of property included in the study sample.
  (1) The comptroller may determine whether a category or class of property in a school district is a major category or class of property to be included in the study on a case-by-case basis. To maximize accuracy or efficient use of resources, the comptroller may decline to sample or estimate category values or measures. If a category or class of property except land qualified for appraisal based on its productive capacity has an appraised value as determined by the CAD of 5.0% or less of the total appraised value of property in categories sampled in the study, the comptroller may decline to sample or estimate the value of that category or class of property.
  (2) The comptroller may determine that a school district split does not have enough value to necessitate that a study be conducted in that portion of the school district. Except in cases where the school district has values split among multiple counties, the comptroller will study at least 85% of the total value for the school district in categories deemed to have enough value to sample.
  (3) If the comptroller does not sample a school district split, a category of property in a school district, or a subcategory of property in a school district, the comptroller may calculate the district's taxable value by using the district's locally reported value to represent the value of the school district split, category, or subcategory not included in the sample.
(f) Taxpayer data. Owners of large unique or complex properties should be advised if these properties are included in the property value study. Taxpayers shall have the option of presenting data to the comptroller to verify the CAD value as representative of market value for inclusion in the study. The comptroller shall have the option of accepting the indicated market value for inclusion in the property value study.
(g) Determining taxable value. The taxable value of certain classes of property shall be determined according to the following appraisal methods:
  (1) Agricultural land qualified for productivity appraisal. The comptroller may determine the productivity value of land qualified for productivity appraisal in a school district through direct appraisal. The staff shall estimate an average value per acre for each land class in each school district using information provided by published sources and by individuals knowledgeable concerning local agricultural conditions. The estimated average productivity value per acre shall be developed using the same methods applicable to appraisal districts under §9.4001 of this title (relating to Valuation of Open-Space and Cont'd...