CHAPTER 2- Collection of Data
Introduction:
In economics, data collection is essential for understanding and analyzing economic activities and problems. Without data, it is impossible to make informed decisions or develop policies. This chapter focuses on the meaning and purpose of data collection, the different types of data (primary and secondary), and the methods used to gather data such as surveys and census.
1. What Are the Sources of Data?
Primary Data: This is firsthand data collected directly from the source. For example, if you conduct a survey among students to find out their opinion about a movie, the results you gather are primary data.
Secondary Data: This data has already been collected and processed by another organization or researcher. Examples include government reports, newspapers, or published books.
2. How Do We Collect Data?
Surveys:
Surveys are used to gather information from individuals about specific topics. Surveys can be conducted through various methods like personal interviews, mailing questionnaires, or telephone interviews.
Questionnaires:
A common tool for data collection is the questionnaire, which can contain open-ended or closed-ended questions. Care must be taken to design clear and concise questions.
3. Different Modes of Data Collection
Personal Interviews:
Researchers meet individuals face-to-face to collect information. This method provides opportunities for clarification and deeper understanding but can be time-consuming and expensive.
Mailing Questionnaires:
Questionnaires are mailed to respondents who are expected to complete and return them. This method is less expensive but may have a lower response rate.
Telephone Interviews:
Data is collected over the phone, which saves time and costs. It is particularly useful when quick responses are needed or when face-to-face interviews are not possible.
4. Census and Sample Surveys
Census (Complete Enumeration):
A census involves collecting data from every individual in the population. It is used for nationwide studies, such as the Indian Census, conducted every 10 years.
Sample Surveys:
A sample is a smaller, representative group selected from the population to gather information. Sampling reduces cost and time compared to a full census. However, care must be taken to avoid bias and ensure that the sample accurately represents the population.
5. Random vs. Non-Random Sampling
Random Sampling:
In random sampling, every individual in the population has an equal chance of being selected. This ensures that the sample is representative of the population. An example is exit polls during elections, where a random sample of voters is surveyed.
Non-Random Sampling:
Non-random sampling involves selecting individuals based on convenience or judgment. This method may introduce bias as not all individuals have an equal chance of being selected.
6. Sampling and Non-Sampling Errors
Sampling Errors: These occur when the sample does not perfectly represent the population. The larger the sample, the smaller the error.
Non-Sampling Errors: These errors occur due to mistakes in data collection, such as misrecording responses or biased questionnaires. These errors can be more serious than sampling errors because they are harder to fix.
7. Census of India and National Sample Survey Organization (NSSO)
The Census of India collects demographic data every 10 years, providing critical information about the size, composition, and distribution of India’s population.
The NSSO conducts periodic surveys on various socio-economic issues like literacy, employment, and consumer expenditure. These surveys help policymakers plan and implement national programs.
Conclusion:
Data collection is a vital process in economics that helps us understand and address various economic issues. Primary data is collected directly through surveys and questionnaires, while secondary data is gathered from existing sources. The method chosen depends on the purpose of the study. Effective data collection provides the foundation for analyzing economic problems and formulating policies to solve them.
Recap:
Data helps in analyzing and solving economic problems.
Primary data is collected firsthand, while secondary data is sourced from other researchers or organizations.
Surveys can be conducted through personal interviews, mail, or telephone.
Census involves collecting data from the entire population, while sampling collects data from a smaller representative group.
Random sampling ensures every individual has an equal chance of being selected.
Sampling errors arise due to the difference between the sample and the population, while non-sampling errors are caused by mistakes in data collection.
