Job openings stem from both replacement needs and employment growth. Replacement needs are expected to account for 63 percent of the approximately 55 million job openings between 1998 and 2008, according to BLS projections.
Professional specialty occupations are projected to grow faster and add more jobs than any other occupational group, with 5.3 million new jobs by 2008. In addition, professional specialty occupations are expected to have 3.9 million job openings due to replacement needs, making this the only major occupational group to have more openings from job growth than replacement needs.
Due to high replacement needs, service occupations are projected to have the largest number of total job openings, 11.1 million. Of these total openings, 3.9 million are expected to be due to job growth and the remainder are expected to be due to replacement. Replacement needs are generally the greatest in the largest occupations and in those with relatively low pay or limited training requirements.
Replacement needs arise as workers leave occupations—some transfer to other occupations while others retire, return to school, or quit to assume household responsibilities. Employment growth refers to job openings that are due to the growth of the economy.
Bureau of Labor Statistics, U.S. Department of Labor, The Economics Daily, Total job openings, 1998-2008: replacement and growth at https://www.bls.gov/opub/ted/2000/mar/wk2/art02.htm (visited February 03, 2023).