allow to take into account the dependence caused by changes in the number of personnel and technical and economic indicators 

involves determining the total and additional need for specialists in the future based on the saturation rates in the base period, taking into account the need to increase or decrease them in the planning period

takes into account changes in the ratio of factors determining the number of employees

involves analysing changes in the number of staff over the past period and transferring the identified trends (with some adjustments) to the values of indicators in the planning period