Primary and Secondary Data
Learn Primary and Secondary Data for GCSE Statistics with this free worksheet and full mark scheme — Foundation and Higher exam-style questions with worked answers for AQA and Edexcel. Primary data are collected first-hand for your own investigation; secondary data come from an existing source.
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These worksheets and mark schemes are original, written for Virtus Academy and checked against the current AQA and Edexcel specifications. Every worksheet comes with a full mark scheme.
Topic overview
Primary data is collected by the person carrying out the investigation, for their own specific purpose. Secondary data has been collected by someone else, for a different purpose.
Primary data has the advantage that it is exactly what is needed, its collection method is known, and its accuracy and reliability can be judged. The disadvantage is that collecting it takes time and money.
Secondary data is quicker and cheaper to obtain, and often covers a much larger population than an individual could survey. The disadvantage is that the collection method may be unknown, it may be out of date, and it may not be in exactly the form required. Census data, published statistics and internet sources are all secondary.
Revision notes
Primary data
Collected by the investigator themselves for their own specific purpose.
Advantages: it is exactly what is needed, the collection method is known, and its reliability can be judged. Disadvantage: collecting it takes time and money.
Secondary data
Collected by someone else, usually for a different purpose.
Examples: census data, published statistics, newspaper reports and internet sources. Advantages: quick, cheap, and often covers a much larger population.
Disadvantages of secondary data
The method of collection may be unknown, so its reliability cannot be judged.
It may be out of date, or may not be in exactly the form needed. There may also be errors introduced when the data was transferred or summarised.
Key points
- Primary data is collected by the investigator.
- Secondary data is collected by someone else.
- Primary data is exactly what is needed.
- Primary data takes time and money to collect.
- Secondary data is quicker and cheaper.
- Secondary data may be out of date.
Worked examples
Example 1
State what is meant by secondary data. [1 mark]
Working
Example 2
Give one advantage and one disadvantage of using secondary data. [2 marks]
Working
Example 3
Explain why primary data may be more reliable than secondary data. [2 marks]
Working
Common mistakes
Calling data primary because you found it yourself.
It is primary only if you collected it; finding published data makes it secondary.
Saying secondary data is always unreliable.
It may be highly reliable — the issue is that you cannot always verify how it was collected.
Giving only advantages.
Evaluation questions want both sides.
Forgetting that secondary data may be out of date.
This is one of the standard disadvantages.
Exam tips
- Ask who collected the data to classify it.
- Give both an advantage and a disadvantage when evaluating.
- Link primary data reliability to knowing the method.
- Name census and published statistics as secondary sources.
Key terms
- Primary data
- Data collected by the investigator for their own purpose.
- Secondary data
- Data collected by someone else.
- Reliability
- How trustworthy and consistent the data is.
- Census data
- A common source of secondary data.
Related topics
Written and reviewed against the current AQA and Edexcel specifications. Spotted an error? Let us know.