Data collection may be defined as the process of procuring information either through survey method or through questionnaire method from the targeted groups for a predefined set of attributes. In other words if I want to know the consumption or standard of living of people of a particular state then I have to float a survey method to capture the information. The numerical form of getting important information is called data collection. For any kind of analysis the data need to be gathered. The data can be of two types, primary and secondary data. Primary data is the data procured by the investigator himself by going to the source of data and gather the information from the respondents directly. Secondary data can be procured from either published sources or unpublished sources. If it is from published sources then there is no need to treat the data statistically, since, it has already been treated and ready for use. If it is from unpublished sources then we have to clean the data and make it compatible for further analysis.  Secondary data are usually in the shape of finished products since they have been treated statistically in some form of the other. After statistical treatment the primary data lose their original shape and become secondary data. Data which are secondary in the hands of one may be primary for others.