Accuracy

One of the most complex yet critical data quality indicator

The degree to which the data item correctly describes the object in context of appropriate real-world context and attributes. The real-world context may be identified as a single version of established truth and used as a reference to identify the deviation of data items from this reference.

Specifications of the real-world references are usually based on business context.

Various Definitions:

The degree to which data factually represents its associated real-world object, event.

The degree to which data correctly describes the “real world” object or event being described The degree to which data values correctly represents real-world entities

The extent to which data are correct, reliable, and certified free of error

The degree to which data has attributes that correctly represent the true value of the intended attribute of a concept or event in a specific context of use

The closeness of the data values to a set of values defined in a domain considered syntactically correct The closeness of the data values to a set of values defined in a domain considered semantically correct

The degree of correspondence between data values to real values

Accuracy can be associated with various levels including metadata. Is the metadata from a verifiable source, and does it describe the data it is attached to correctly? For example, if the metadata is a definition, does the definition correctly define the data element in question?

Measuring Accuracy

The degree to which the data mirrors the characteristics of the real world object or objects it represents.

Unit of Measure: The percentage of data entries that pass the data accuracy rules.

Related Dimension: Validity is a related dimension because, in order to be accurate, values must be valid, the right value and in the correct representation.

Example(s): A European school is receiving applications for its annual September intake and requires students to be aged 5 before the 31st August of the intake year.

In this scenario, the parent, a US Citizen, applying to a European school completes the Date of Birth (D.O.B) on the application form in the US date format, MM/DD/YYYY rather than the European DD/MM/YYYY format, causing the representation of days and months to be reversed.

As a result, 09/08/YYYY really meant 08/09/YYYY causing the student to be accepted at the age of 5 on the 31st August in YYYY.

The representation of the student’s D.O.B.–whilst valid in its US context–means that in Europe the age was not derived correctly and the value recorded was consequently not accurate.