Organisations often assume that changes in recruitment policy will quickly change the composition of their workforce.
In practice, this is rarely the case.
Workforces behave like systems. The overall composition of employees is shaped not only by recruitment, but also by promotion patterns, career length and exit rates. These forces often cause the workforce to move toward a stable balance that can change only slowly.
In the Diversity Maths framework, these stable outcomes are referred to as “Stubborn States.”
Understanding them is essential when organisations set targets for workforce composition.
A simple example
Consider a large investment company with:
- 30,000 employees
- 30% women
- staff evenly distributed across ages.
Suppose employees join the firm at age 21 and typically leave at age 50. Ignoring mortality, this gives a 30-year career span.
With 30,000 staff across 30 age groups, this means roughly:
1,000 employees at each age.
Because the workforce is 30% female:
- 300 women leave the firm each year
- 700 men leave each year.
These departures must be replaced by new recruits.
A new diversity target
Now suppose the CEO sets a goal of increasing female representation from 30% to 50%, broadly reflecting the UK population.
A natural response might be to change recruitment patterns.
Let us assume the company begins recruiting 1,000 graduates each year, split:
- 500 women
- 500 men
The incoming class is therefore 50% female.
But what happens to the workforce overall?
After the first year
Before the change:
- Women: 9,000
- Men: 21,000
After one year:
Women leaving: 300
Women recruited: 500
New total:
9,000 − 300 + 500 = 9,200
Men leaving: 700
Men recruited: 500
New total:
21,000 − 700 + 500 = 20,800
Total workforce remains 30,000.
The proportion of women becomes:
9,200 / 30,000 = 30.7%
Despite recruiting a cohort that is 50% female, the overall workforce has increased by less than one percentage point.
The long time horizon
The organisation wants to move from 30% to 50% women, a change of 20 percentage points.
At roughly 2 percentage points every three years, this process would take approximately:
30 years
to reach the target.
In other words, workforce composition changes slowly because the existing workforce turns over gradually.
This is a classic example of a Stubborn State.
Could faster recruitment change help?
If exit rates are fixed, the only lever available is recruitment composition.
Suppose the firm attempted a very aggressive strategy and recruited 100% women.
Even then, the mathematics of workforce turnover means the target would be reached only after roughly 8–9 years.
However, recruitment policies of that type may raise practical or legal concerns, and in reality organisations typically recruit from populations where the gender balance is not so extreme.
For example, among high-achieving graduates the female proportion may be around 58%.
If recruitment rose to around 68% female, the model suggests that the 50% workforce target would be reached in around 15–16 years.
Why this surprises organisations
Many diversity strategies assume that workforce composition can change within five to ten years.
In large organisations with long career spans, the mathematics of turnover often makes such timelines difficult to achieve.
This does not mean change is impossible. Rather, it highlights the importance of understanding the structural dynamics of the workforce before setting targets.
Common objections
When organisations see these results, several common responses arise.
“Our firm recruits people older than 21.”
This slightly shortens career length, but the overall effect is usually limited. Later recruitment ages are often accompanied by later retirement ages.
“People leave and are replaced.”
True — but if exit rates are modest and replacements resemble those leaving, the overall composition changes slowly.
“Our firm is growing.”
Growth does accelerate change, but the effect is often smaller than expected. Even significant growth rates may reduce the timeline only modestly.
“Tie-break rules can favour under-represented groups.”
Tie-break provisions can influence outcomes at the margin, but they affect only a small number of decisions within a large recruitment process.
Looking beyond recruitment
Recruitment is only one factor shaping workforce composition.
Other influences may include:
- promotion patterns
- retention rates
- the attractiveness of the organisation to different groups.
Understanding these dynamics can be as important as recruitment policy itself.
Why Stubborn States matter
Many organisations publish ambitious diversity goals without fully modelling how workforce dynamics will influence the speed of change.
The Stubborn States model, part of the Diversity Maths toolkit, allows organisations to test these assumptions.
Using company-specific data on recruitment, promotion and attrition, the model can simulate thousands of possible scenarios and estimate how quickly workforce composition is likely to change.
This provides leadership teams with a clearer picture of:
- realistic timelines for change
- the recruitment patterns required to reach particular targets
- the structural factors that may slow progress.
In short, it allows diversity strategy to move from aspiration toward evidence-based planning.