What is the difference between primary and secondary data in an investigation?

• A. Primary data are direct observations and recordings; secondary data are derived or interpreted information from other sources.
• B. Primary data are derived or interpreted information from other sources; secondary data are direct observations
• C. Primary data are opinions; secondary data are numerical measurements
• D. Primary data are published reports; secondary data are field notes

Answer: (A)

The key distinction is about the origin of the data: whether you collected it yourself or used information someone else gathered and possibly interpreted. Primary data are direct observations and recordings you collect firsthand—measurements, field notes, experimental results, or any data you generate yourself. Secondary data come from sources that already exist and are derived or interpreted from other sources—published reports, articles, databases, summaries, or analyses produced by others.

This matters because primary data give you control over how and when the information was gathered, which is crucial for the investigation’s credibility and methodology. Secondary data provide context, background, or corroboration, but you’re relying on someone else’s collection and interpretation.

Why the other statements don’t fit: one option says primary data are derived or interpreted information from other sources, which describes secondary data, not primary. Another implies primary data are opinions and secondary are numerical measurements; data types aren’t what define primary versus secondary—it's about source. Another suggests primary data are published reports and secondary data are field notes; field notes are typically primary data you collected, while published reports are usually secondary.