PRIMARY AND SECONDARY DATA (Statistics) – Complete Notes for Competitive Examinations
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PRIMARY AND SECONDARY DATA
Introduction
Statistics is the science of collecting, organizing, presenting, analyzing and interpreting data. Data is the foundation of statistics. The quality of statistical analysis depends upon the quality of data collected.
According to the source of collection, data is classified into:
Primary Data
Secondary Data
This is one of the most important topics for competitive examinations because several objective questions are asked every year.
What is Data?
Data refers to facts, figures, observations or information collected for analysis.
Examples
Population of a village
Marks of studentsMonthly income
Rainfall records
Crop production
Age of employees
Classification of Data Based on Source
Data
│
├── Primary Data
│ (Collected first-hand)
│
└── Secondary Data
(Already collected by others)
PRIMARY DATA
Definition
Primary data is the data collected for the first time by the investigator directly from the original source for a specific purpose.
It is also called First-hand Data or Original Data.
Simple Definition
Data collected directly by the researcher for his own investigation is known as Primary Data.
Features of Primary Data
Original in nature
Collected for a specific purposeHighly reliable
More accurate
Costly
Time-consuming
Collected directly from respondents
Examples of Primary Data
Example 1
A teacher asks every student in the class about their daily study hours.
➡ This is Primary Data.
Example 2
Government officers visit every house during the Census and collect information.
➡ Primary Data
Example 3
A company conducts a customer satisfaction survey.
➡ Primary Data
Example 4
A hospital collects blood pressure readings from patients.
➡ Primary Data
Advantages of Primary Data
High accuracy
ReliableSpecific to objectives
Latest information
Better quality
Greater control over collection
Disadvantages of Primary Data
Expensive
Time-consumingRequires trained investigators
Difficult for large populations
Needs planning
METHODS OF COLLECTING PRIMARY DATA
This is one of the most important exam topics.
1. Direct Personal Investigation
The investigator personally meets respondents and collects information.
Example
A teacher personally asks students their marks.
Advantages
Most accurate
Reliable
Personal verification possible
Disadvantages
Expensive
Suitable only for small areas
2. Indirect Oral Investigation
Information is collected from witnesses, experts or third persons.
Example
Police asking neighbours about an incident.
Used When
Respondents unavailable
Sensitive matters
Crime investigation
3. Information Through Local Correspondents
Local agents regularly send information to a central office.
Example
Newspapers collecting rainfall reports from district reporters.
4. Mailed Questionnaire Method
Questionnaires are sent through post or email.
Respondents fill them and return.
Advantages
Cheap
Covers large area
Disadvantages
Low response rate
Delay
5. Schedule Method
Enumerator visits respondents and fills the schedule himself.
Example
Population Census
This is one of the most reliable methods.
6. Telephone Interview
Questions are asked over phone.
Advantages
Fast
Less expensive
Disadvantages
Limited questions
Network problems
7. Online Survey
Using Google Forms, Apps or Websites.
Examples
Online customer feedback.
SECONDARY DATA
Definition
Secondary data is the data already collected by someone else for another purpose and used later by another researcher.
It is also called Second-hand Data.
Features of Secondary Data
Already available
Collected by others
Less expensive
Saves time
Less reliable than primary data
May not suit objectives completely
Examples of Secondary Data
Census Reports
RBI Reports
NSSO Reports
Government publications
Newspapers
Books
Journals
Research papers
World Bank reports
WHO reports
Advantages of Secondary Data
Cheap
Saves time
Easily available
Large coverage
Useful for comparison
Disadvantages
May be outdated
Accuracy uncertain
Different objectives
Incomplete information
Possible bias
Sources of Secondary Data
A. Published Sources
Government Publications
Census Reports
Economic Survey
RBI Publications
NSSO Reports
Books
Journals
Newspapers
Magazines
International Organizations
Internet
B. Unpublished Sources
Company records
School records
Hospital records
Research reports
Personal diaries
Office files
Difference Between Primary Data and Secondary Data
| Basis | Primary Data | Secondary Data |
|---|---|---|
| Meaning | First-hand data | Already collected data |
| Collected by | Investigator himself | Someone else |
| Nature | Original | Not original |
| Purpose | Specific | Different purpose |
| Cost | High | Low |
| Time | More | Less |
| Accuracy | High | Comparatively lower |
| Reliability | High | Depends on source |
| Availability | Not readily available | Easily available |
| Examples | Survey, Census, Interview | Books, Census Report, RBI Report |
How to Choose Between Primary and Secondary Data
Choose Primary Data when:
High accuracy is needed
Latest information is required
Specific objectives exist
Choose Secondary Data when:
Time is limited
Budget is small
Background information is needed
Important Examination Facts
Primary Data = Original Data
Secondary Data = Already Existing Data
Census data is Primary for the government but Secondary for researchers.
Schedule is filled by Enumerator.
Questionnaire is filled by Respondent.
Primary Data is expensive.
Secondary Data is economical.
Direct investigation gives maximum accuracy.
Online surveys are becoming increasingly popular.
Memory Trick
PRIMARY
P – Personal collection
R – Reliable
I – Investigator collects
M – More accurate
A – Authentic
R – Real-time
Y – Your own data
SECONDARY
S – Someone else collected
E – Economical
C – Cheap
O – Old data possible
N – Not original
D – Different purpose
A – Already available
R – Ready to use
Y – Yield quick results
Frequently Asked Competitive Examination Questions
Q. Census data is Primary for whom?
Answer: Government
Q. Census data is Secondary for whom?
Answer: Researchers using Census reports.
Q. Which method is used in Population Census?
Answer: Schedule Method
Q. Who fills the Questionnaire?
Answer: Respondent
Q. Who fills the Schedule?
Answer: Enumerator
Q. Which data is more reliable?
Answer: Primary Data
Q. Which data is cheaper?
Answer: Secondary Data
Q. Which data requires more time?
Answer: Primary Data
Multiple Choice Questions (MCQs)
1. Data collected first-hand by the investigator is called:
A. Secondary Data
B. Classified Data
C. Primary Data
D. Tabulated Data
Answer: C
2. Which of the following is original data?
A. Census Report (used by a researcher)
B. RBI Report
C. Primary Data
D. Newspaper
Answer: C
3. Which method is used in Population Census?
A. Telephone Interview
B. Schedule Method
C. Questionnaire
D. Observation
Answer: B
4. Questionnaire is filled by:
A. Enumerator
B. Investigator
C. Respondent
D. Government Officer
Answer: C
5. Schedule is filled by:
A. Respondent
B. Enumerator
C. Student
D. Teacher
Answer: B
6. Which data is less expensive?
A. Primary Data
B. Secondary Data
C. Experimental Data
D. Census Data
Answer: B
7. Which data is generally more reliable?
A. Secondary Data
B. Primary Data
C. Published Data
D. Historical Data
Answer: B
8. Government publications are an example of:
A. Primary Data
B. Secondary Data
C. Experimental Data
D. Classified Data
Answer: B
9. Information collected from witnesses is called:
A. Direct Investigation
B. Indirect Oral Investigation
C. Observation
D. Census
Answer: B
10. Which method is fastest today?
A. Personal Interview
B. Online Survey
C. Mail Survey
D. Schedule Method
Answer: B
Statement-Based MCQs
1. Consider the following statements:
Primary data is collected for the first time.
Secondary data is collected by the investigator himself.
Choose the correct answer:
A. Only 1
B. Only 2
C. Both
D. Neither
Answer: A
2. Consider the following statements:
Questionnaire is filled by respondents.
Schedule is filled by enumerators.
A. Only 1
B. Only 2
C. Both 1 and 2
D. Neither
Answer: C
3. Consider the following statements:
Primary data is more expensive.
Secondary data is always more accurate than primary data.
A. Only 1
B. Only 2
C. Both
D. Neither
Answer: A
4. Consider the following statements:
RBI reports are a source of secondary data.
Census data is always primary data for every user.
A. Only 1
B. Only 2
C. Both
D. Neither
Answer: A
5. Which of the following statements are correct?
Primary data is original in nature.
Secondary data saves time and cost.
Primary data is collected by someone else.
A. 1 and 2 only
B. 2 and 3 only
C. 1 and 3 only
D. 1, 2 and 3
Answer: A
One-Liner Revision (Exam Booster)
Primary Data = First-hand + Original + Reliable.
Secondary Data = Second-hand + Economical + Ready to use.Questionnaire → Filled by Respondent.
Schedule → Filled by Enumerator.
Primary Data is costly and time-consuming.
Secondary Data is inexpensive and quick to obtain.
Direct Personal Investigation provides the highest accuracy.
Population Census primarily uses the Schedule Method.
Government reports, RBI reports, NSSO publications, and books are common sources of Secondary Data.
For competitive examinations, remember: Original = Primary; Already available = Secondary.