Elementary Statistics (1+1)

2.1.5 Difference between primary and secondary data

The difference between primary and secondary data is only of degree – data which are primary in the hands of one become secondary in the hands of another. Data are primary for the individual agency or institution collecting them whereas for the rest of the world they are secondary. A few examples would clarify the distinction. Suppose an investigator wants data about the spending habits of the students of Delhi University. If he collects the data himself or through his agents adopting any suitable method such as contacting and interviewing students or circulating a questionnaire, the data would constitute primary data for him. On the other hand, if the students union has already made a similar survey and the investigator obtained data from union office, such data would constitute secondary data for him. Similarly, statistics collected by various departments of the Government such as Labour Bureau and Central Statistical Orgainisation are primary for the respective departments whereas for all others they are secondary data.