919.459.6097 info@reso.org  

Data Dictionary Workgroup

On Going Growth

The workgroup purpose is to maintain and develop the Dictionary. The RESO Dictionary is designed to grow with our industry. If you have ideas for the dictionary we welcome them. However your ideas for change do require some accompanying information.

  • Name: Please review like fields or enumerations and create a name you feel best fits the current convention.
  • Definition: We ask that you write a robust definition of the field.
  • Data Type: Include your recommended data type and maximum field length.
  • Enumerations: If your recommended field is a pick-list, please include enumerations. Enumerations will also need a robust definition.
  • Justification: Please give a reason the field is important to your market. Also if the field has legal or MLS rules requirements, be sure to include a reference back to the law or rules in question.
  • Utilization: We ask that you include an indication of how much use your field or enumeration sees. This should be done by a count of the number of listings are using the field or enumeration and the number of listings in your sample. This will be used to create a percentage of utilization. Include the criteria used to determine the sample of listings used.

Thank you for your interest and participation in the Data Dictionary. More information will be following form RESO about implementing the Dictionary in existing and future versions of RETS. We also invite all MLSs to refer to the dictionary as a future center for their own metadata (field/enumeration) change decisions.


Rob Larson is the workgroup chair. The workgroup meets monthly on the 3rd Thursday from 12:00 – 1:00 PM EST. If you want to join the meeting, please contact info@reso.org.

Data Dictionary

The RESO Dictionary has two purposes.

  1. Serve as a non-RETS guideline for a national standard for the fields and look-ups (enumerations) in the MLS.
  2. Common center for all expressions of fields and enumerations in the RETS standard.

As an MLS reviews change it is advised to consider the benefits of growing closer to the national standard. Not only will it make the effort of ensuring RETS compliance easier, it will also ensure that as listings progress through IDX and other aggregation points, it will help to ensure that the meaning of your data is not diluted or misinterpreted.

As the RETS Standard has grown, it has become abundantly clear that a “common ground” for fields and enumerations is needed. Whether it be the separation between Standard Names in older versions of RETS or the growth of diverse payloads, by keeping a central requirement to express property and listing concepts in a uniform fashion will mitigate implementation errors, ease field mapping and foster innovation around a more stable and cost effective center.

The Dictionary is broken down into the following tabs. Please review the following details and information on use of the dictionary.

  • Meta-Definitions: This page should be reviewed first. It contains the definitions about the fields used in the RESO Dictionary to define the fields and look-ups.
  • Recommendations: List of suggested Data Dictionary changes including discussion notes.
  • RESO Dictionary: Each Data Dictionary resource will have its own tab containing fields and their defining details. Dictionary tabs include: Property, Member, Office, Media and History.
  • Enumerations: This tab has the list of enumerations, or pick lists, that have been defined thus far. Keep in mind, that unless “locked” all lists are extensible.
  • Deleted Elements: These are fields or enumerations that have been deleted from the dictionary.
DLU April 14th, 2016