Collection of Data Class 11 Economics

Introduction

Data collection is the systematic process of gathering information for analysis. It plays a vital role in research, decision-making, and problem-solving across various fields. From surveys and interviews to sensors and digital platforms, data collection methods continue to evolve, driving innovation and insights in today's data-driven world. 

What are the Sources of Data?

Statistical data can be obtained from two sources:

• Primary data
• Secondary data

Primary Data

The important points of primary data are:

• The enumerator (person who assembles the data) may collect the data by administering an inquiry or research. Such data is called Primary Data, as it is formulated on first-hand information.
• Primary data are unique, do not require any modification, and are costly.

Secondary data

• If the data have been examined and analyzed by another agency, they are called Secondary Data. Usually, the issued data are secondary.
• They are already in the present and therefore are not unique.
• It demands to be modified to satisfy the aim of the study at hand.
• Secondary data are low-priced.

How do we collect Data?

It is done in the following ways:

Surveys

• The survey aims to describe characteristics like cost, worth, utility (in the case of the product) reputation, honesty, and loyalty (in the case of the nominee).
• The objective of the survey is to gather data and is a method of gathering information from individuals.

Preparation of Instrument

The most prevalent type of tool employed in surveys is a questionnaire/ interview schedule. The questionnaire is either self-directed by the interviewee or conducted by the enumerator or qualified investigator. While drawing up the questionnaire/interview schedule, the following points should be kept in mind:

• The questionnaire should not be lengthy.
• The array of problems should move from indefinite to distinct.
• Questions should not be enigmatic.
• Questions should not use binary negatives. 
• Questions should not be leading.
• Questions should not indicate choices. 

Mode of Data Collection

The aim of probing questions is to survey the acquisition of data. There are three ways of collecting data: 

• Personal Interviews
• Mailing (questionnaire) Surveys
• Telephone Interviews

Personal Interviews

In this method, the researcher has the main role as he/she conducts the interviews face-to-face with the respondents. Personal interviews are preferred due to various reasons:

• Highest Response Rate 
• Allows use of all types of questions 
• Better to use open-ended questions 
• Allows clarification of ambiguous questions.

The personal interview has some demerits too:

• Most expensive 
• Possibility of influencing respondents 
• More time taking

Mailing Questionnaire

In such a method, the data is collected through the mail. The questionnaire is mailed to each person and a request is attached to complete and return it on time. 

The advantages of this method are:

• Least expensive 
• The only method to reach remote areas 
• No influence on respondents 
• Maintains anonymity of respondents 
• Best for sensitive questions

The disadvantages of mail surveys are:

• It cannot be used by illiterates 
• Long response time  
• Does not allow an explanation of unambiguous questions  
• Reactions cannot be watched 

Telephone Interviews

In telephone interviews, the investigator asks questions over the telephone. 

The advantages of telephone interviews are:

• Relatively low cost 
• Relatively less influence on respondents 
• Relatively high response rate.

The disadvantages of this method are:

• Limited use 
• Reactions cannot be watched 
• Possibility of influencing respondents

Pilot Survey

• After the questionnaire is ready, it is desirable to carry out a try-out with a diminutive group, known as the Pilot Survey or Pre-Testing of the questionnaire. 
• The pilot survey serves to give a preliminary impression of the survey. 
• It helps to pretest the questionnaire and know the lapses and drawbacks.
• It also aids in assessing the appropriateness of questions, the accuracy of guidance, the administration of enumerators, and the expense and time required in the actual survey.

Census and Sample Surveys

• A survey, which encompasses every component of the population, is apprehended as a Census or the Method of Complete Enumeration.
• The primary feature of this approach is that this comprises every individual unit in the whole population.

• A sample refers to a section of the population from which information has to be taken. A good sample (representative sample) is usually short and competent in giving reasonably accurate information about the population at a lower cost and in less time.
• Most of the surveys are sample surveys and are preferable in statistics because of several reasons.
• A sample can give rationally secure and authentic information at a lower cost and in less time. 
• Now the question is how do you do the sampling? There are two main types of sampling:
  • Random Sampling
  • Non-random Sampling

Random Sampling

• It is also known as the lottery method.
• Random sampling is where the specific units from the population (samples) are randomly selected. 
• In random sampling, each person has an equal possibility of being chosen, and the person who is selected is the same as the one who is not selected.
• Random number tables are generated to ensure an equal chance of selection of every single unit in the population.
• They are accessible either in an issued form or can be generated by employing relevant software packages.

Non-random sampling

• In this method, units of the population don’t have equal chances of being selected. 
• The convenience or interpretation of the investigator plays a crucial role in the adoption of the sample. 
• They are chiefly selected based on belief, purpose, ease, or quota and are non-random samples.

Sampling and Non-sampling Errors

Sampling errors

• Sampling error applies to the variations between the sample estimate and the actual value.
• It is the error that transpires when you observe the sample taken from the population. 
• The point of differentiation between the actual parameter of the population and its estimate is known as sampling error. 

Non-sampling errors

Non-sampling errors are more consequential than sampling errors. Sampling error can be minimized by taking a larger sample, on the other hand, it is difficult to minimize non-sampling error. Even a Census can carry non-sampling errors.

 Some of the non-sampling errors are:

• Errors in Data Acquisition: This type of error stems from recording inaccurate responses.
• Non-Response Errors: Non-response happens if an interviewer is incapable of contacting a person listed in the sample or a person from the sample declines to respond. In this case, the sample research may not be representative.
• Sampling Bias: Sampling bias happens when the sampling plan is such that some portion of the target population could not possibly be incorporated into the sample.

Census of India and NSSO

• The Census of India and the National Sample Survey Organisation (NSSO), are two significant firms at the national level, which gather, manner, and tabulate data.
• The Census of India produces the most comprehensive and continuous demographic record of the population. 
• The NSSO was established by the Government of India to conduct nationwide surveys on socio-economic issues. 
• NSSO gives periodic measures of education, school enrolment, utilization of educational aids, employment, unemployment, manufacturing, and service sector enterprises, morbidity, maternity, child care, utilization of the public distribution system, etc.