When projecting occupational employment, Lightcast estimates the change in new jobs and replacement jobs with the Openings, and Annual Openings figures. New jobs capture the change in the total number of workers employed in an occupation (the difference between the base and projection years), while replacement jobs are estimates of workers permanently leaving the workforce. A combination of both numbers indicates total openings for the projection period. That total is divided by the number of projected years to get the Annual Openings.

The replacements job portion reflects ratios of likely replacement needs taken from the Working Futures publication. Some examples of what constitute "replacement" include:

The takeaway is a worker permanently leaving the workforce. What is not counted here is when a worker leaves the region but continues in the same line of work or changes occupation. Similarly, if a worker remains both in the region and in his or her occupation but moves to a different company, this is not counted as a replacement need.

Openings can be thought of as a conservative measure of job demand. Combining job growth with replacement needs can account for much of the demand in a region, but also excludes job needs that result from workers migrating out or moving to new companies within the region.