Learn in the textbookClassifying Data by Attribute and Structure
DefinitionSecondary data (2次データ) is data already collected for another purpose that you reuse in your own analysis.
ExplanationExamples include national and local government statistics, industry association reports, and materials published by research firms. It is quick and cheap to obtain, but the survey period or how items are defined may not match your purpose, so check how it was produced before relying on it.
AnalogyLike a ready-made dish bought at the store. You can eat it right away, but you do not get to choose the seasoning.