How Does the Gap Evolve to the Future Organisation?
The single biggest mistake in the traditional approach to the workforce planning gap analysis is how the delta between the current workforce and the future demand is established. These are two snapshots of distinct points in time: a photograph of today and a painting of the desired state at the end of the planning horizon.
To plan against the traditional gap is to embark on an interplanetary flight, where a rocket flies through the vacuum of space until it reaches the final destination. It is an approach that ignores the necessity for an organisation to conduct business throughout the planning horizon and is prevalent in horizon two and three approaches.
In reality, workforce planning is like sailing a vessel to an island; setting forth on the ocean and adjusting the rudder and the sails as the winds change and the waves hit.

To illustrate the difference between the two, the two charts above have an x-axis of time and a y-axis of the value of whichever of the seven rights we are looking at.
For example, in assessing the Right Size, the values on the x-axis would be either the headcount or FTE of the workforce. In an organisation that aims for growth, the derived demand will translate into an increase for a higher number of workers. During the same period, the supply of workers will always decrease due to turnover. These aspects are identical in both charts.
More traditional approaches assess and plan on a single variant, the gap between the current level of supply to the future level of demand (shown as Gap a). In this instance, the approach is ignorant of the change that will naturally take place within the workforce. This approach often results in restructures and redundancies, dismissing workers equivalent to what would have departed anyway during the planning horizon.
Contemporary thinkers have recognized this issue and recommend an approach that compares both the workforce and demand at the end of the planning horizon (shown as Gap b). This, unfortunately, ignores a second critical flaw of the traditional approach. By its very nature, it overlooks the demand requirements over the course of the planning horizon; no consideration is given to the achievement of organisational goals and objectives before the endpoint. Such an approach, as we can imagine, would be disastrous for an organisation to implement. As a result, this traditional approach lies behind the common problem of being unable to translate workforce plans into action.
Instead, in the agile approach, we examine the gap throughout all the points in the evolution towards the end of the planning horizon. The gap is multivariant, in that it is based on every point of the supply being contrasted against every proceeding instance of the demand. The reason for this is that traditional workforce planning has treated the gap between supply and demand as a constant factor in the organisation. Therefore, aiming to bridge the gap at a future point in time is clearly better than never bridging the gap.