Collection of Statistical Data - primary and Secondary Data

Statistics - Generally it refers to the science that stores quantitative information. But, to a student of economics, it is much beyond that. It involves the study of the methods and techniques of collecting, classifying and analysing the store of quantitative information with a view to getting some meaningful conclusions.
  • Types of Data
  1. Primary and Secondary Data
  2. Univariate and Bivariate Data
  3. Quantitative and Qualitative Data
  4. Nominal and Ordinal Data
  5. Time Series and Cross Section Data
  • Primary Data: Data Collected by the investigator for his own purpose, 2the first time, from beginning to end, are called primary data. These are collected from the source of origin. 
  • Note: If you are getting data from somebody else who collected it from its source of origin but did not use it for his own study, it will be deemed as primary data.
  • Secondary Data: Data Collected by other persons are called secondary data.
  • Methods of collecting primary data:
  1. Direct Personal Investigation
  2. Indirect oral Investigation
  3. Information from Local Sources or Correspondent
  4. Information through Questionnaires and Schedules. - (i) Mailing Method  (ii) Enumerator's Method 
  • Direct Personal Investigation - it is the method by which data are personally collected by the investigator from the informants. 
  • Indirect Oral Investigation: It is the method by which information is obtained not from the persons regarding whom the information is needed. It is collected orally from other persons who are expected to possess the necessary information. These other persons are known as witnesses.
  • 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 the investigator.
  • Information through Questionnaires and Schedules: Under this method, the investigator prepares a questionnaire keeping in view the objective of the enquiry. There are two ways of collecting information on the basis of questionnaire: (1) Mailing Method and (2) Enumerator's Method.
  1. Mailing Method: Under this method, questionnaires are mailed to the informants. A letter is attached with the questionnaire giving the purpose of enquiry. It is also assured that the information would be kept secret. The informant notes the answers against the questions and returns the completed questionnaire to the investigator.
  2. Enumerator's Method: Under this method, a questionnaire is prepared according to the purpose of enquiry. The enumerator himself approaches the informant with the questionnaire. The questionnaires which are filled by the enumerators themselves by putting questions are called schedules. Thus, under this method, the enumerator himself fills the schedules after seeking information from the informants. Enumerators are those persons who help the investigators in collecting the data. The enumerators are given training to fill the schedules and put the questions intelligently to obtain accurate information.