We can obtain some data from an internal data source, such as an organization’s operating and accounting records. These routine data are usually saved in computer data files or databases for efficient entry, storage, and retrieval of information. Internal data is obtained from inside the company for successful operations. The information obtained from internal data source is important to determine the company strategies. We usually obtain data from external data sources. External data sources may be a reference book or statistical periodical published by a government agency, a trade association, or a private service company.