EconomicsCBSE Class 11 · Collection of Data

Primary and Secondary Data, Questionnaires and the Pilot Survey

Updated 17 October 2026 · Fact-checked

Primary data are collected first-hand by the investigator for a specific purpose; secondary data are already collected by others, from sources such as government publications. Methods of primary collection include personal interview, mailed questionnaire and telephone. A good questionnaire has few, clear, ordered questions, and a pilot survey tests it on a small group before the main survey.

Primary data are collected first-hand, often with a questionnaire that is tested in a pilot survey; secondary data already exist in publications.

Illustration drawn for QuestionBuddy.

Understand Primary and Secondary Data and Questionnaire

Primary and secondary data.

Primary data: collected by the investigator directly from the field for the first time, for a specific purpose. Advantages: suited to the objective, reliable control; disadvantages: costly and time-consuming.
Secondary data: already collected for another purpose and available in publications such as government reports (Census, National Sample Survey, Economic Survey), journals, newspapers and websites. Advantages: quick and cheap; disadvantages: may not fit the purpose, may be outdated or inaccurate.

Methods of collecting primary data.

Personal interview: the investigator meets the respondent; high response, can clarify questions; costly; interviewer bias possible.
Mailed questionnaire: sent by post/email; cheap, covers wide areas; low response rate and cannot clarify questions; needs literate respondents.
Telephone interview: quick and cheap but limited to people with phones and with short questions.

Questionnaire (a set of questions to get information). A good questionnaire has:

Few questions, only those needed for the objective.
Short, simple, clear and unambiguous wording, one idea per question.
Logical order, from simple to difficult; avoid personal or embarrassing questions early.
No leading questions (questions suggesting an answer) and no questions needing calculation or memory of distant events.
Types: closed (fixed options such as yes or no) and open (free response); multiple choice.
Clear instructions and a courteous introduction.

Pilot survey. A small-scale trial of the questionnaire on a few respondents before the full survey, to find ambiguities, wrong order or missing options, and to estimate time and cost; the questionnaire is then revised.

Response rate = (responses received ÷ questionnaires sent) × 100.

Sources of secondary data. Government (Census of India, National Sample Survey Office), international organisations, research institutes, newspapers, websites. Check the source, date, definitions and coverage before using.

Flow chart: objective → draft questionnaire → pilot survey → revise → main survey → data.

Primary and Secondary Data and Questionnaire: key facts

Response rate: Responses received / questionnaires sent x 100; Mailed surveys
Primary vs secondary: Primary = first-hand, specific | Secondary = existing, published; Source of data
Questionnaire: Few
clear
ordered
no leading questions; Qualities
Pilot survey: Small trial
revise questionnaire
then main survey; Test

How to answer Primary and Secondary Data and Questionnaire questions

Questions ask to classify data as primary or secondary, evaluate a questionnaire or compute a response rate.

1Decide: did the user collect it first-hand (primary) or take it from a published source (secondary)?
2Check each question for clarity, bias and order.
3Compute response rate as responses over sent times 100.
4State the advantage and disadvantage of the chosen method.
5Explain the pilot survey's purpose.

Primary and Secondary Data and Questionnaire in real life

The idea, met in an everyday situation. Answer the question in your own words, then compare with the model answer. The one-line hook is what to remember.

School canteen survey

Suppose a class prepares a questionnaire on canteen food and tests it with 10 students before the full survey. Three of them find one question confusing.

What is this step called and what should the class do?

Try it first, then show the solutionSolution

It is a pilot survey.
The class should reword or remove the confusing question.
Then the revised questionnaire can be used for the main survey.

Answer: Pilot survey, then revise.

Memory hook: Test first, fix, then survey.

Tricks to remember Primary and Secondary Data and Questionnaire

Short memory aids. Say each one aloud once, then use it on a question the same day.

Prime = first-hand
Primary data: collected first-hand.
Use it when: Primary
Second-hand
Secondary data: someone else collected.
Use it when: Secondary
Few, Clear, Ordered, Neutral
Questionnaire qualities: FCON.
Use it when: Questionnaire

Primary and Secondary Data and Questionnaire: solved examples

Ordered from board level to HOTS. Try each one before you open the solution.

Example 1: Primary or secondary · 3 marks · Short answerBoard level

Classify as primary or secondary: (a) a student interviews 30 shopkeepers (b) a student uses data from the Census report (c) a school collects heights of its own students.

Try it first, then show the solutionSolution

(a) primary (1 mark).
(b) secondary (1 mark).
(c) primary for the school (1 mark).

Answer: Primary, secondary, primary.

Example 2: Questionnaire qualities · 2 marks · Very short answerBoard level

State four qualities of a good questionnaire.

Try it first, then show the solutionSolution

Few and relevant questions; clear and simple language (1 mark).
Logical order and no leading questions (1 mark).

Answer: Few, clear, ordered, neutral.

Example 3: Response rate · 3 marks · Short answerHarder board level

A mailed questionnaire sent to 240 households receives 180 replies. Find the response rate and comment on the reliability.

Try it first, then show the solutionSolution

Response rate = 180 / 240 x 100 (1 mark).
= 75 per cent (1 mark).
A good rate, but the 25 per cent who did not reply may differ, so bias should be checked (1 mark).

Answer: 75 per cent.

Example 4: Faulty questions · 3 marks · Short answerHarder board level

Identify the fault in: (a) Do you not agree that the new bus service is excellent? (b) What was your monthly expenditure on milk in 2005? Rewrite each.

Try it first, then show the solutionSolution

(a) Leading question suggesting the answer (1 mark).
(b) Depends on distant memory (1 mark).
Rewrite: How would you rate the bus service? and What did you spend on milk last month? (1 mark).

Answer: Leading; memory-dependent.

Example 5: Choosing the method · 5 marks · Long answerHOTS / competency

Suppose a researcher must survey 5,000 widely spread, mostly illiterate farmers on credit use. Evaluate mailed questionnaire, personal interview and telephone, and recommend one with a pilot survey.

Try it first, then show the solutionSolution

Mailed questionnaire needs literacy and has low response, so unsuitable (1 mark).
Telephone is limited by phone access and short questions (1 mark).
Personal interview suits illiterate respondents and allows clarification (1 mark).
It is costly and time-consuming and risks interviewer bias, so train the interviewers (1 mark).
Run a pilot survey to refine questions before the main study (1 mark).

Answer: Personal interview with a pilot survey.

Where students lose marks in Primary and Secondary Data and Questionnaire

The slips examiners see most often, and what to write instead.

Mistake: Secondary data as own survey
Source confusion.
Wrong working
Data from a report are primary.
Right working
They are secondary for the user.
Do this: Who collected?
Usually costs: 1 mark.
Mistake: Response rate inverted
Formula flipped.
Wrong working
Rate = sent / replies.
Right working
Rate = replies / sent x 100.
Do this: Replies on top.
Usually costs: 1 mark.
Mistake: Skipping pilot survey
Purpose unknown.
Wrong working
Pilot survey is the main survey.
Right working
It is a small trial before the main survey.
Do this: Test.
Usually costs: 1 mark.

Exam tips

Define primary and secondary with an example from the question.
Show response-rate working.
Give reasons for the method chosen.
Mention pilot survey whenever a questionnaire appears.

Practice questions on Primary and Secondary Data and Questionnaire

Write each answer on paper first. Open the hint only if you are stuck, and the answer only when you have finished.

Q1 · 1 mark · MCQBoard level
Data taken from a published government report are
(a) primary (b) secondary (c) raw (d) qualitative
Hint
Existing.
Answer
(b).
Q2 · 1 mark · Assertion-reasonHarder board level
Assertion (A): A pilot survey is conducted before the main survey.
Reason (R): It helps find faults in the questionnaire.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.
Hint
Trial run.
Answer
(a).
Q3 · 2 marks · Very short answerBoard level
Give two advantages of using secondary data.
Hint
Cheap and quick.
Answer
It is cheaper and faster than collecting new data, and it may cover large areas or long periods already.
Q4 · 4 marks · Case-basedHarder board level
Read and answer.
Suppose a questionnaire sent to 500 people has 125 replies.
(a) Find the response rate. (1)
(b) Name the method. (1)
(c) Give one disadvantage of the method. (2)
Hint
Mailed.
Answer
(a) 125 / 500 x 100 = 25 per cent. (b) Mailed questionnaire. (c) Low response rate and no way to clarify doubts.
Q5 · 3 marks · Short answerHOTS / competency
Suppose a survey on household savings asks, "How much do you save, and do you save less than your neighbours?" in one question. Identify the problems and redesign the question set.
Hint
Double and sensitive.
Answer
The question is double-barrelled and sensitive. Split it: ask the amount saved last month, and in a separate neutral question ask about saving habits without comparing with neighbours.

Test your recall

Answer in your head or on paper first, then open the card. Pulling an answer out of memory makes it stick far better than re-reading.

1.Primary data?Show answer
First-hand data.
2.Secondary data?Show answer
Existing published data.
3.Pilot survey?Show answer
Small trial of a questionnaire.
4.Leading question?Show answer
One that suggests the answer.
5.Response rate formula?Show answer
Replies / sent x 100.
6.Secondary source?Show answer
Census report.

Primary and Secondary Data and Questionnaire: frequently asked questions

What is primary data?

Data collected first-hand.

What is secondary data?

Data already collected and published.

Why a pilot survey?

To test and improve the questionnaire.

What is a questionnaire?

A set of questions for collecting information.

What is a mailed questionnaire?

A form sent by post or email for respondents to fill in.