Which description best distinguishes accuracy from completeness in safety data?

• A. Completeness reflects the missingness of entire crash records and individual record elements, while accuracy reflects the degree to which data is error-free and non-duplicative.
• B. Completeness means all data are correct; accuracy means all fields are present.
• C. Completeness and accuracy are the same.
• D. Accuracy reflects data timeliness; completeness reflects data volume.

Answer: (A)

In safety data, two quality dimensions matter: completeness and accuracy. Completeness is about what data is present or missing. If a crash record is missing or a field in a record is blank, the data set isn’t complete because pieces of information are absent. Accuracy, on the other hand, is about whether the information that is there is correct and unique. Data can be present but still be wrong, and duplicates can inflate numbers or misrepresent events, which harms accuracy.

So the best description is that completeness reflects missingness of entire crash records and individual record elements, while accuracy reflects the degree to which data is error-free and non-duplicative. The other statements mix these concepts or bring in timeliness or volume, which aren’t what completeness and accuracy measure.