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Workforce Demand (WFD)

The Workforce Demand evaluation (WFD) is a
prediction of the evolution of the required workforce,
exploiting a “What-If” scenario to get insight into the
business policies’ infl uence on the future personnel
structure. Thus, the main goal of the WFD study is to
estimate present and future workforce requirements
to execute a project [3]. As mentioned by Huang
[4], the total demand must be in form of “projects”
skill requirements [man-hours per skill or job-role].
The overall workforce demand should be composed Fig. 1 Regression Analysis example over two skills
of: the demand for future projects, the demand for
the projects in execution, the demand of the work By exploiting the equations in fi g.1 and assuming
backlogs, and the demand coming from possible a x future project expenditure, the workforce hours
trend changes. Each project should be also defi ned demanded per skill can be foreseen. The presented
by size, duration, and arrival time (if new) [4]. model is suitable for medium to big size project-
Concerning the operative calculation of the demanded oriented companies, able to provide a relevant
workforce for future projects, the literature proposes sample of past projects not too distant in time (old
four main methods considered highly compatible projects might have recurred to different techniques
with project-driven contexts because strictly related and methods).
to the single project.
3. The Ad hoc Simulator (SimMan) (SIM) is a tool
1. The Labor Multiplier (LM) approach assumes that in developed and presented by Huang [4]. It assumes
each project type, the projects will have the same level that each incoming project belongs to one of the pre-
of labor requirements per unit of project expenditure, specifi ed sets of “project types” and as such should
and will follow standard patterns [5]. Based on the be defi ned in size (the total man-hours required)
past projects’ labor deployment per skill and their and duration (the amount of calendar time required
expenditure, the number of laborers for each trade/ to be completed). A project type is specifi ed by
job role in form of [man-days/€] for individual type the proportion of different required skills (based on
of project can be derived. For example, a company historical data). For example, knowing that a project
producing two products, “Tank” and “Burner”, might of the “Tank” type requires 20% of the total hours
calculate, based on the past data, that for every expected to be covered by employees with drawing
100.000€ of expenditure in the design phase of a competencies, and knowing that its size could
project classifi ed as “Tank”, 150 hours of employees be 2.000 hours,
with designing skills and 100 hours of employees the workforce This study aims to investigate
with analysis skills will be required. Furthermore, for with drawing skills current knowledge on WFP by
every 100.000€ of expenditure in the construction required for the
duration
phase of a project classifi ed as “Tank” type, 100 project’s “aiming at the recognition of
hours of welding skills will be needed. This method will amount to 400 its key characteristics, in order
is recommended to all organizations, especially small hours. The project
to medium size companies, due to its need for data type and its size can to build a high-level guideline
coming from only a few past projects, its simplicity, be considered valid that is generally considered
and its acceptable accuracy. On the other hand, it alternative predictors valid in project-oriented
requires to be constantly updated alongside the of the project’s
technological and methodological improvements. demand. Labor organizations
Multiplier, Linear
2. The Linear Regression (LR) model is a time series Regression and Ad
forecasting method that identifi es historical patterns hoc Simulator are the best candidates for the static
in past data to extrapolate future trends. The cost quantitative evaluation of the workforce demand.
of the project and the type of the project are good However, in order to include the dynamic changes
predictors of future manpower requirements. As a which are likely to modify the project’s expectations,
consequence, once the costs and labor deployments the researchers focused on System Dynamics (SD).
per skill or job role (e.g., drawing and welding) from
at least 30 completed projects of the same type have 4. System Dynamics (SD) is an objective-oriented
been collected, it is possible to estimate the future methodology able to introduce cause-and-effect
labor hours per skill, knowing the expected cost of relations between system variables by using causal
the future project. Excel allows to show, as an option loop diagrams [6]. It allows the exploration of how
of the scatter plot (fi g.1), the linear trend relationship project changes affect the project variables respon-
between project cost and labor for each skill, together sible for the defi nition of the workforce demand, pro-
with the mathematical equation which rules it. In the moting the “What-If” scenario simulation. Assuming
case of low R (max 1), the use of this method is not the division of a construction project into three pha-
2
recommended. ses, design, construction, and test, where each ge-

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