Class 11 Economics , statistics

4. Principal differences between Primary and
Secondary data
Primary Data Secondary Data
1. More Original 1. Less Original
2 . Specific Objective 2 . Already collected for
some other purpose
3 . More costly in terms 3 . Less costly in terms
of time, money and of time, money and
efforts efforts

5. For the collection of primary data the investigator
can follow any of the following methods –
 Direct Personal Investigation
Indirect oral investigation
Information from local sources
Information through questionnaire an schedules
i. Mailing method ii. Enumerator’s method

6. 1.Direct personal investigation-
The direct personal investigation is the method
by which data is personally collected by the
investigator from the informants. The
investigator should be very diligent, efficient,
impartial and tolerant.
Suitability –
1.Field of investigation is limited.
2.A greater degree of originality of the data is
required .
3.Information is to be kept secret.
4.Accuracy of data is of great significance.

8. Indirect Oral investigation –
Under indirect oral investigation information is not collected
from the person regarding whom information is needed. It is
collected orally from other persons who are expected to
posses the necessary information. These other persons are
known as witnesses.
Suitability-
1. Field for investigation is too large.
2. Direct contact with informant is not possible.
3. Informant is not capable to give answers.
4. Informant is not likely to give right answers.
5. Only experts can give right answers .

9. Merits Demerits
1.Wide coverage 1. Less accurate
2. Less expensive 2. Bias of witness
3. Expert Opinion 3. Doubtful conclusion
4. Free from Bias of investigator
5. Simple

10. Mode of Data collection
3. Information from local sources or correspondents –
Under this method the investigator appoints local persons or
correspondents at different places. They collect information in their
own way and furnish the same to investigator.
Advantages Disadvantages
1. Economical 1. Lack of Originality
2. Wide coverage 2. Lack of Uniformity
3. Continuity 3. Personal Bias
4. Suitable for special purposes 4. Delay in collection
like where we need continuous
information

11. 4

13. Mode of Data Collection
5. Enumerator’s Method –
Under this method enumerator himself approaches the
informant with the questionnaire. The questionnaire which
are filled by the enumerators themselves by putting
questions are called schedules.
Advantages Disadvantages
1. Wide Coverage 1. Expensive
2. Accuracy 2. Time consuming
3. Impartiality 3. Availability of
enumerators

14. Published Sources-
1. Government publications
2. Semi government publications
3. Reports of committees and commissions
4. Publications of Trade associations
5. Publications of research institutes
6. Journals and papers
7. publications of research scholars
8. International publications
Unpublished Sources

15. Precautions in the use of
Secondary data –
1.Ability of the collecting
organization
2.Objective and scope
3.Method of collection
4.Time and conditions of
collection
5.Definition of the unit
6.Accuracy

18. HOTS Questions –
1.”Census of India provides statistical information on various
aspects of demographic changes in India.” Explain.
2. “Secondary data are those which are already in existence,
and which have been collected, for some other purpose than
the answering of the question in hand.” Substantiate this
statement focusing on the difference between primary and
secondary data.
3. Differentiate between questionnaire and schedule.
4. What precautions must be taken while preparing a
questionnaire.
5. “Statistical tables giving district wise death and birth rates
(number of deaths and births per 1000 of population) are
obtained from publications of census of India 2011. Would you
call them primary or secondary data ? Give two reasons in
support of your answer.

19. Reports and publications of NSSO-
National sample survey organization is a
government organization under the
ministry of Statistics and programme
implementation. This organization
conducts sample surveys regularly to
collect information like
1. Land and livestock farming
2. Housing conditions and migration
3. Employment and unemployment status
etc.