Workforce Shape is a top level measurement that shows the target and actual counts of managers vs. producers in an organization in one dimension and the number of contractors vs. full-time staff on the other axis.
There should be more producers than managers in an organization, keeping an eye on the ratio between them and ensuring it's healthy can stop resource creep in middle management. Similarly, large organizations tend to have a significant contractor workforce which is flexed over time depending on current needs. Making sure that the balance is right between staff and contractors is part of workforce management.
The Workforce Shape on the right is only for explanation of the measure - it does not indicate a recommended workforce shape! The graph shows a target workforce shape (green) with a roughly equal contractor/staff workforce with a roughly 1:3 ratio between managers and producers. The ratio of managers to producers is normally around 1:10 or less, the split between contractors and permanent staff is dependent on the business in question.
The actual workforce shape is indicated by the blue overlay - this shows that there is a roughly equal split between managers and producers (likely to be highly dysfunctional) which is below the target ratio. The actual workforce also has slightly too many contractors and not enough staff - although this can often be caused by resource pipeline difficulties, in this example, the ratio is currently below target.
Ideal resource levels are described in the Governance view.