The numerical SIC codes are also used to tabulate data on industries and to access many databases of industrial information, such as the Thomas and Standard and Poor's Registers. The CIP includes coded classifications and definitions of program purpose. To provide links between these various systems, cross-references or crosswalks were created. Because of the amount and diversity of LMI, selecting the most appropriate sources may seem like an overwhelming task. Some materials, developed for recruiting or publicity purposes, may overstate the demand for an occupation, future earnings potential, and so forth.
Materials produced for the purpose of vocational guidance usually are the most objective.
Regardless of how comprehensive and reliable a source was when it was initially published, if the underlying facts or data become dated, it may then contain obsolete or misleading information. Some organizations, such as the Bureau of Labor Statistics' Division of Occupational Outlook, have earned a reputation for developing reliable materials. However, there are also organizations with vested interests that tend to develop self-serving materials. A number of resources have been developed to help teachers and counselors make better use of LMI in career decision making. Brief descriptions of three are provided here.