for a loss of 10,000 employees. However, the actual employment loss was only 2,000 employees, but that equals the sum of the three effects (5,000 gain + 3,000 gain + 10,000 loss). The analysis implies that local factors lead to a decrease in 10,000 employees in the state construction industry, because the growth in both the national economy and the construction industry should have increased state construction employment by 8,000 employees (the 5,000 national share effect plus the 3,000 industry mix effect). Names and regions Shift-share analysts sometimes use different labels for the three effects, although the calculations are the same. National growth effect may be referred to as national share. Industry mix effect may be referred to as proportional shift. Local share effect may be referred to as differential shift, regional shift, or competitive share. In most shift-share analyses, the regional economy is compared to the national economy. However, the techniques may be used to compare any two regions (e.g., comparing a county to its state). Dynamic model In 1988, Richard Barff and Prentice Knight, III, published the dynamic model shift-share analysis. In contrast to the comparative static model, which only considers two years in its analysis (the beginning and ending years), the dynamic model utilizes every year in the study period. Although it requires much more data to perform the calculations, the dynamic model takes into account continuous changes in the three shift-share effects, so the results are less affected by the choice of starting and ending years. The dynamic model is most useful when there are large differences between regional and national growth rates, or large changes in the regional industrial mix. The dynamic model uses the same techniques as the comparative static model, including the same three shift-share effects. However, in the dynamic model, a time-series of traditional shift-share calculations are performed, comparing each year to the previous year. The annual shift-share effects are then totaled together for the entire study period, resulting in the dynamic model's shift-share effects. Formula The regional change in the variable within industry between the two years and is defined as the sum of the three shift-share effects: national growth effect (), industry mix effect (), and local share effect (). If the study period ranges from year to year , then traditional shift-share effects are calculated for every year , where spans from to . The dynamic model shift-share effects