Secondary data refers to data that is collected by someone other than the primary user.[1] Common sources of secondary data for social science include censuses, information collected by government departments, organizational records and data that was originally collected for other research purposes.[2] Primary data, by contrast, are collected by the investigator conducting the research.
Secondary data analysis can save time that would otherwise be spent collecting data and, particularly in the case of quantitative data, can provide larger and higher-quality databases that would be unfeasible for any individual researcher to collect on their own. In addition, analysts of social and economic change consider secondary data essential, since it is impossible to conduct a new survey that can adequately capture past change and/or developments. However, secondary data analysis can be less useful in marketing research, as data may be outdated or inaccurate.[1]