Sources of Secondary Data Internal Sources. All companies collect information about their business and much of it can be valuable to the marketing manager. Sales reports, the MIS, purchase orders, and other company documents can supply managers with a great deal of information. Libraries contain substantial reference materials and usually access to one or more on-line computerized databases designed to search for information quickly. Government data can be useful for estimating the size of markets.
Government information is also very inexpensive.
Many organizations specialize in developing valuable secondary information. Firms like Claritas, Nielsen, and Donnelley Marketing Service can often provide secondary information cheaper than a firm can gather it. Source of Primary Data Primary data collection also offers several alternatives for obtaining information marketing managers need.