ISO/IEC 11179 Part 4 Rules and Guidelines for the Formulation of Data Definitions

1. ISO/IEC 11179 Part 4 Rules and Guidelines for the Formulation of Data Definitions Lois Fritts SAIC January 17, 2000 Open Forum onMetadata Registries Santa Fe, NM SDC-0002-021-JE-2022

2. Data element definitions and descriptions are often insufficient to support reuse or multiple users of data. Data element names are often not definitive for value domains. Data standardization must focus on data element definitions rather than names. Challenges

3. Purpose of Definitions The purpose of a data element definition is to define a data element with words or phrases that describe, explain, or make definite and clear its meaning.

4. A data definition shall be: Unique Singular A statement of concept, not its negative A descriptive phrase or sentence Commonly understood abbreviations Without embedded definitions Data Definition Rules

5. Distinguishable from every other definition within the registry. Good - The date when a regulation became effective. The date when collection of the sample began. Poor - The date when something started. Unique

6. Always expressed in the singular. Good - The unique identification number assigned to a facility. Poor - Unique identification number assigned to facilities. Singular

7. Cannot exclusively say what it is not. Good - The name of a facility that is recognized by the local community as the commercial name. Poor - The name of a facility that is not the legal name. Positive, Not Negative

8. Include the essential characteristics of the concept.Good - The name of the individual designated to be the facility’s representative for communications about the facility. Poor - Person to contact. Descriptive

9. Use only commonly known abbreviations. Good - The Standard Industrial Classification (SIC) code that represents the economic activity of a company. Poor - The SIC code that represents the economic activity of a company. Avoid Abbreviations

10. Second concept should not appear in the definition. Good - The text that describes the method used to calibrate an instrument. Poor - The text that describes the method used to calibrate an instrument, where calibration is the process of rectifying the graduation of quantitative instruments. No Embedded Definitions

11. State the essential meaning of the concept. Be precise and unambiguous. Be concise. Be able to stand alone. Be expressed without embedding rationale, functional usage, domain information or procedural information. Avoid circular reasoning. Use consistent terminology and structure for related definitions. Data Definition Guidelines

12. Avoid non-essential characteristics. Good - The name of a country where mail is delivered. Poor - The last line of a mail piece that names the country where mail is delivered. Essential Meaning

13. Express exact meaning of the concept. Good - The calendar date when latitude and longitude coordinates were determined. Poor - The data collection date. Precise and Unambiguous

14. Comprehensive without extraneous terms. Good - The name of the person to contact for clarification of technical information. Poor - The individual EPA or State officials maycontact if clarification of the information reported on the form is required. Concise

15. Stand alone without further definition. Good - The Hydrologic Unit Code (HUC) that represents a surface drainage basin or a combination of drainage basins. Poor - The Hydrologic Unit Code (HUC) that represents a cataloging unit. Stand Alone

16. Does not include rationale, functional usage, or procedural information. Good - The distance in meters above or below a reference surface. Poor - The distance above or below a reference surface, measured in meters rather than feet, because meter is an international unit of measure. Without Embedded Rationale

17. A data element should not be defined in the context of another data element. Poor - Facility Identification Number–The number assigned to a facility. Facility–The site identified by a facility identification number. Avoid Circular Reasoning

18. A common terminology and syntax.Good - The code that represents the method used to determine vertical coordinates. The name of the method used to determine vertical coordinates. Poor - The code that represents the method used to determine horizontal coordinates. The name of the method used to determine the latitude and longitude of a place. Consistent with Related Data

19. Use a phrase, not a sentence. The name of the country where mail is delivered. Begin the definition by stating the representation class, such as: The name of…. The code that represents…. The text that describes…. The measure of the…. Thenumber assigned by…to identify…. The sum, dimension, capacity (quantity) of…. Example Definition Syntax

20. Must state exactly the same concept. Same - The measure of elevation in meters, above or below a reference datum (Registry). The vertical distance in meters either above or below a reference surface (Standard). Different - The height or depth of a facility relative to sea level. Definitions in Context

21. Good definitions promote the standardization and reuse of data elements, leading to data sharing and integration of information systems. SDC-0002-021-JE-2022