Evaluating Data Reliability in Hybrid Appraisal Assignments

Real estate appraiser working at desk assessing data reliability

In completing bifurcated and hybrid appraisals, you must reasonably believe that information relied upon—from a third-party inspector or another data source—is reliable. You, the appraiser, should have a process for evaluating data reliability by asking the following questions:

  • Who collected the data?
  • Is the data source unbiased and objective?
  • Does the data source have a reputation of trustworthiness and accuracy?
  • How old is the data collected?
  • Is the data consistent with data available from other sources?

Below, we share some possible data sources and verification resources that can be used in determining data reliability. Additionally, we examine three characteristics you may consider to determine whether the quality and quantity of data available about the subject’s relevant characteristics is sufficient to develop a credible appraisal.

Various available data sources

Here is a list of some of the various available data sources that may be used in collecting information about the subject property’s relevant physical characteristics:

  • Tax assessing offices
  • State or County Department of Environmental Quality
  • Environmental data maps available by state, city, and zip code on epa.gov
  • Planning and building departments
  • Board of Realtors®
  • Multiple Listing Service (MLS) or public databases
  • For Sale by Owner websites
  • Courthouse or Recorder’s records
  • FHFA Home Price Index
  • HUD, USDA, VA, Fannie Mae, Freddie Mac (economic data and relevant characteristics required for type of loan)
  • Aerial or satellite maps
  • University research centers
  • Craig’s List (for rental house information)
  • Private individuals—attorneys, real estate agents, property managers, builders, etc.
  • Property owners
  • Local newspapers and free publications
  • Data aggregators
  • Appraiser or appraisal office records

Take a deep dive into bifurcated appraisals with our new CE course: Best Practices for Completing Bifurcated and Hybrid Appraisals.

Data types and sources available are numerous, and it is not possible to list all data sources that could be used to solve specific appraisal problems. Additionally, none of these data sources are applicable for all property types, locations, or appraisal assignments. For example, if appraising a working farm, the local MLS is unlikely to be the best source of data, but it may be an excellent data source for a tract home located in a subdivision for a hybrid appraisal.

Determining data reliability

In order to reasonably believe that a source is reliable, it is recommended that you assess the dependability of a data source based on the following three characteristics, at a minimum: accuracy, trustworthiness, and timeliness.


Is the data source known to be typically correct, factual, consistent, and precise? Is the data required to be entered in a uniform format? In other words, a data source such as the MLS may require certain data points such as site size to be entered in a consistent and specific data format.


Is the data source considered to be objective, impartial, and credible?


Is the data from a time period suitable for the appraisal’s effective date? How often is the data updated? Data would be measured on timeliness if it is a dynamic record rather than a static record.

For example, if an appraiser was confirming the year built of the subject dwelling and found that it was built in 1955, she could rely on this data even though its reporting date was 10 years ago since the year built does not change over time. However, the appraiser would not want to rely on MLS data that is 10 years old for determining the property’s current condition, modernization, and quality for an appraisal with a current effective date. The subject home may have undergone remodeling or renovations over the past 10 years or the subject dwelling may not have been maintained over the past 10 years, either of which could drastically impact the appraisal assignment results.

For a more detailed discussion on data reliability, as well as many other aspects of completing hybrid appraisal assignments, take our CE course: Best Practices for Completing Bifurcated and Hybrid Appraisals.

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