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Collection of DataUNIT 5 COLLECTION OF DATA

Objectives

After studying this unit, you should be able to:

appreciate the need and significance of data collection

distinguish between primary and secondary data

know different methods of collecting primary data

design a suitable questionnaire

edit the primary data and know the sources of secondary data and its use at

understand the concept of census vs. sample.

Structure

5.1 Introduction

5.2 Primary and Secondary Data

5.3 Methods of Collecting Primary Data

5.4 Designing a Questionnaire

5.5 Pre-testing the Questionnaire

5.6 Editing Primary Data

5.7 Sources of Secondary Data

5.8 Precautions in the Use of Secondary Data

5.9 Census and Sample

5.10 Summary

5.11 Key Words

5.12 Self-assessment Exercises

5.13 Further Readings

5.1 INTRODUCTIONTo make a decision in any business situation you need data. Facts expressed in

quantitative form can be termed as data. Success of any statistical investigation

depends on the availability of accurate and reliable data. These depend on the

appropriateness of the method chosen for data collection. Therefore, data collection is

a very basic activity in decision-making. In this unit, we shall be studying the

different methods that are used for collecting data. Data may be classified either as

primary or secondary.

5.2 PRIMARY AND SECONDARY DATAData used in statistical study is termed either "primary" or "secondary" depending

upon whether it was collected specifically for the study in question orfor some otherpurpose. When the data used in a statistical study was collected under the control and

supervision of the investigation, such type of data is referred to as "primary data".

When the data was not collected by the investigator, but is derived from other sources

then such data is referred to as "secondary data".

The difference between primary and secondary data is only in terms of degree. For

example, data which is primary in the hands of one become secondary in the hands of

another. Suppose an investigator wants to study the working conditions of labour in a

big industrial concern. If he collects the data himself or through his agent, then this

data is referred to as primary data. But if this data is used by someone else, then this

data becomes secondary data.

5.3 METHODS OF COLLECTING PRIMARY DATAPrimary data may either be collected through the observation method or through the

questionnaire method.

In the observation method, the investigator asks no questions, but he simply observes

5

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the phenomenon under consideration, and records the necessary data. Sometimes

individuals make the observation; on other occasions, mechanical and electronic

devices do the job.

In the observation method, it may be difficult to produce accurate data, Physical

difficulties on the part of the observer may result in errors. Because of these

limitations in the observation method, the questionnaire method is morewidely used

for collecting data. In the questionnaire method, the investigator draws up

questionnaire containing all the relevant questions which he wants to ask from his

respondents, and accordingly records the responses. Questionnaire method may beconducted' through personal interview, or by mail or telephone.

Personal Interviews: In this method the interviewer sits face-to-face with the

respondent and records his responses. In this method, the information is likely to be

more accurate and reliable because the interviewer can clear up doubts and cross-

checks the respondents. This method is time-consuming and can be very costly if the

number of respondents is large and widely distributed.

Mail Questionnaire: In this method a list of questions (questionnaire) is prepared

and mailed to the respondents. The respondents are expected to fill in the

questionnaire and send it back to the investigator. Sometimes, mail questionnaire are

placed in respondents' hands through other means such as attaching them to

consumers' products or putting them in newspapers or magazines. This method canbe easily adopted where the field of investigation is very vast and the respondents are

spread over a wide geographical area. But this method can be adopted only where

the. respondents are literates and can understand written questions and answer them.

Telephone: In this method the investigator asks the relevant questions from the

respondents over the telephone. This method is less expensive but it has limited

application since only those respondents can be interviewed who have telephones;

moreover, very few questions can be asked on telephone.

The questionnaire method is a very efficient and fast method of collecting data. But it

has a very serious limitation as it may be extremely difficult to collect data on certain

sensitive aspects such as income, age or personal life details, which the respondent

may not be willing to share with the investigator. This is so with other methods alsodifferent people may interpret the questions differently and consequently there may

be errors and inaccuracies in data collection.

Activity A

Explain clearly the observation and questionnaire methods of collecting primary data.

Highlight their merits and limitations.

Activity B

Describe the personal interviews and mail questionnaire method of data collection.

.

Activity C

Point out the advantages of telephonic method of data collection. Does it have any

limitations?

.

Once the investigator has decided to use the questionnaire method, the next step is to

draw up a design of the survey.

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Collection of Data

a)

b)

c)

A survey design involves the following steps:

Designing a questionnaire

Pre-testing a questionnaire

Editing the primary data.

5.4 DESIGNING A QUESTIONNAIRE

The success of collecting data through a questionnaire depends mainly on how

skilfully and imaginatively the questionnaire has been designed. A badly designedquestionnaire will never be able to gather the relevant data. In designing the

questionnaire, some of the important points to be kept in mind are:

Covering letter:Every questionnaire should contain a covering letter. The covering

letter should highlight the purpose of study and assure the respondent that all

responses will be kept confidential. It is desirable that some inducement or

motivation is provided to the respondent for better response. The objectives of the

study and questionnaire design should be such that the respondent derives a sense of

satisfaction through his involvement.

Number of questions should be kept to the minimum: The fewer the questions, the

greater the chances of getting a better response and of having all the questions

answered. Otherwise the respondent may feel disinterested and provide inaccurateanswers particularly towards the end of the questionnaire. Informing the questions,

the investigator has to take into consideration several factors such as the purpose of

study, the time and resources available. As a rough indication, the number of

questions should be between 15 to 40. In case the number of questions is more than

25, it is desirable that the questionnaire be divided into various parts to ensure clarity.

Questions should be simple, short and unambiguous: The questions should be

simple, short, easy to understand and such that their answers are unambiguous. For

example, if the question is: `Are you literate?' the respondent may have doubts about

the meaning of literacy. To some literacy may mean a university degree whereas to,

others even the capacity to read and write may mean literacy. Hence it is desirable to

specify whether you have passed (a) high school (b) graduation (c) post graduation

etc. Questions can be of Yes/No type, or of multiple choice depending on therequirement of the investigator. Open- ended questions should generally be avoided.

Questions of sensitive or personal nature should be avoided; The questions should

not be such as would require the respondent to disclose any private, personal or

confidential information. For example, questions relating to sales, profits, marital

happiness etc. should be avoided as far as possible. If such questions are necessary in

the survey, an assurance should be given to the respondent that the information

provided shall be kept strictly confidential and shall not be used at any cost to their

disadvantage.

Answers to questions should not require calculations: The questions should be

framed in such a way that their answers do not require any calculations.

Logical arrangement:The questions should be logically arranged so that there is a

continuity of responses and the respondent does not feel the need to refer back to the

previous questions. It is desirable that the questionnaire should begin with some

introductory questions followed by vital questions crucial to the survey and ending

with some light questions so that the overall impression of the respondent is a happy

one.

Cross-check and Footnotes: The questionnaire should contain some such,questions

which act as a cross-check to the reliability of the information provided. For example,

when a question relating to income is asked, it is desirable to include a question: "Are

you an income tax assessee?"

For the purpose of clarity, certain questions which might create a doubt in the mind

of respondents, it is desirable to give footnotes. The purpose of footnotes is to clarifyall possible doubts which may emerge from the questions and cannot be removed

while answer them. For example, if a question relates to income limits like 1000-

2000, 2000-3000; etc., a person getting exactly Rs. 2000 should know in which

income class he has to place himself.

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One specimen format for a questionnaire used by IGNOU to elicit background of the

participants and their expectations from the Diploma in Management course is shown

below:

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Data Collection andAnalysis

INDIRA GANDHI NATIONAL OPEN UNIVERSITYSCHOOL OF MANAGEMENT STUDIES

DIPLOMA IN MANAGEMENT

OBJECTIVE-EXPECTATION ASSESSMENT FORMAT

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Activity D

You have been directed, by your employer to carry out a market survey to ascertain

the probable demand for the new drug your company is going to introduce. Prepare a

suitable questionnaire in this connection. State also the type of respondents you

expect to cover.

5.5 PRE-TESTING THE QUESTIONNAIREOnce the questionnaire has been designed, it is important to pre-test it. The pre-

testing of a questionnaire is also known as pilot surveybecause it precedes the main

survey work. Pre-testing allows rectification of problems, inconsistencies, repetitions

etc. If changes are required, the necessary modifications can be made before

administering the questionnaire, some questions are found irrelevant, they can be

deleted and if some questions have to be included, the same can be done. Pre-testing

must be done with utmost care, otherwise unnecessary and unwanted changes may beintroduced. If time and resources permit, a second pre-testing can also be done to

ensure greater reliability of results. Proper testing, revising and re-testing would yield

high dividends.

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extra-cautious in using secondary data and he should not accept it at its face value.

The reason may be that such data is full of errors because of bias, inadequate sample

size, errors of definitions and computational errors etc. Therefore, before using such

data, the following aspects should be considered.

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Collection of Data

Suitability. The investigator must ensure that the data available is suitable for the

purpose of the inquiry on hand. The suitability of data may be judged by comparing

the nature and scope of investigation.

Reliability. It is of utmost importance to determine how reliable is the data fromsecondary source and how confidently we can use it. In assessing the reliability, it is

important to know whether the collecting agency is unbiased, whether it has a

representative sample, the data whether has been properly analysed, as so on.

Adequacy. Data from secondary sources may be available but its scope may be

limited and therefore this may not serve the purpose of investigation. The data may

cover only a part of the requirement of the investigator or may pertain to a different

time period.

Only if the investigator is fully satisfied on all the above mentioned points, he should

proceed with this data as the starting point for further analysis.

5.9 CENSUS AND SAMPLE

When secondary data is not available for the problem under study, a decision may be

taken to collect primary data through original investigation. This original

investigation may be obtained either by census (or complete enumeration) method or

sampling method. When the investigator collects data about each and every item in

the population, it is known as the census method or complete enumeration survey.

But when the investigator studies only a representative part of the total population

and makes inferences about the population on the basis of that study, it is known as

the sampling method. In both the situations, the investigator is interested in studying

some characteristics of the population.

The advantage of the census method is that information about every item in the

population can be obtained. Also the information collected is more accurate. The

main limitations of the census method are that it requires a great deal of money and

time. Moreover in certain practical situations of quality control, such as finding the

tensile strength of a steel specimen by stretching it till it breaks is not even physically

possible to check each and every item because quality testing result in the destruction

of the item itself. In most cases, it is not necessary to study every unit of the

population to draw some inference about it. If a sample is representative of the

population then our study of the sample will yield correct inference about the total

population.

It should be noted that out of the census and sampling methods, the sampling methodis much more widely used in practice. There are several methods of sampling which

would be discussed in detail in unit 13 on `sampling methods'.

5.10 SUMMARY

Statistical data is a set of facts expressed in quantitative form. The use of facts

expressed as measurable quantities can help a decision maker to arrive at better

decisions. Data can be obtained through primary source or secondary source. When

the data is collected by the investigator himself, it is called primary data. When the

data has been collected by others it is known as secondary data. The most important

method for primary data collection is through questionnaire. A questionnaire refers toa device used to secure answers to questions from the respondents. Another important

distinction in considering data is whether the values represent the complete

enumeration of some whole, known as population or universe, or only a part of the

population, which is called a sample.

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5.11 KEY WORDS

Census is the collection of each and every item in the given population or universe.

Population is the collection of items on which information is required.

Primary Data is the collection of data by the investigator himself.

Questionnaire is a device for getting answers to questions by using a form to which

the respondent responds.Sample is any group of measurements selected from a population.

Secondary Data is the collection of data compiled by someone other than the user.

5.12 SELF-ASSESSMENT EXERCISES

1 Distinguish between primary and secondary data. Discuss the various methods of

collecting primary data. Indicate the situation in which each of these methods

should be used.

2 Discuss the validity of the statement: "A secondary source is not as reliable as a

primary source."3 Discuss the various sources of secondary data. Point out the precautions to be

taken while using such data.

4 Describe briefly the questionnaire method of collecting primary data. State the

essentials of a good questionnaire.

5 Explain what precautions must be taken while drafting a useful questionnaire.

6 As the personnel manager in a particular industry, you are asked to determine the

effect of increased wages on output. Draft a suitable questionnaire for this

purpose.

7 It you were to conduct a survey regarding smoking habits among students ofIGNOU, what method of data collection would you adopt? Give reasons for your

choice.

8 Distinguish between the census and sampling methods of data collection and

compare their merits and demerits. Why is the sampling method unavoidable in

certain situations?

9 Explain their `population' and `sample'. Explain why it is sometimes necessary

and often desirable to collect information about the population by conducting a

sample survey instead of complete enumeration.

5.13 FURTHER READINGSClark, T.C. and E.W. Jordan, 1985.Introduction to Business and Economic Statistics,

South-Western Publising Co.: Ohio.

Elms,P.G. 1985.Business Statistics, Richard D. Irwin Inc.: Homewood.

Gupta, S.P. and M.P. Gupta, 1988.Business Statistics, Sultan Chand & Sons: New

Delhi.

Levin, R.I. 1979. Statistics for Management, Prentice Hall of India: New Delhi.

Moskowiz H. and G.P. Wright, 1985. Statistics for Management and Economics,

Charles E. Meri11 Publishing Company: Ohio.