The management “breeding machine” – how hierarchies swell the upper ranks

Here is a small quiz … An organisation starts with 250 junior staff, 50 mid-level, and 10 senior leaders. Then:

… each year, 10% of seniors leave (so average tenure is 10 years)

… and we promote 10% of mid-level staff, and another 20% of mid-level people leave

… and we promote 30% of juniors, another 30% of juniors leave, and we hire enough to replace both of those losses from the junior group.

How many staff will we have at each level after 10 years?

How the physics works

Here’s the answer! – probably not news to HR professionals, but it may surprise others.
(if you built a model for this, don’t forget to add the numbers to get to the end of year 10)

block diagram showing we get to 250 juniors, 246 mid-level and 145 seniors

… and here’s how we get there – not exactly intuitive, but that’s what the “physics” does …

charts showing 10-year pattern for each group - juniors static at 250, mid-level grow fast from initial 50, then tail off to 246, seniors grow nearly straight line from 10 to 145

This outcome is not such a puzzle – if we have many times more people at a lower level than an upper level, then promoting even a small % from that lower level can easily more-than replace the people who leave from the upper level.

It is a slightly smaller problem if we are growing – growing juniors by 10%/year gives you 713 juniors, 532 mid-level and 221 seniors after 10 years. But the supervisory ratios are still squished from the 25 : 5 : 1 we start with. Even 20%/year growth does not keep the organisation in balance, ending with 1858, 1113, 344 people in the three groups. 


So we must:

either promote fewer people – but mid-level folk are already waiting 10 years for promotion, and juniors are waiting 3 years

… and/or clear out upper levels more quickly. (This is why consulting firms operate an ‘up or-out’ policy, in which senior staff are retired early, and staff at other levels must seek promotion after a few years, or they are out-placed – usually to client organisations)

All of this may explain some common issues:

  • a tendency to invent more levels in the hierarchy, so people can be promoted, though at a financial cost from lower supervisory ratios
  • a serious aging problem in mature businesses – we don’t move older staff on, so cannot recruit or promote younger staff
  • a widespread population of jobless early-middle-aged professionals, though some then start their own businesses, or else join the ranks of the sole-trader consultants.

What’s for sure is that our staffing strategy needs to deal with this challenge!

This is one example of resource “pipelines” – other pipelines bringing challenges of their own are found in the development and capture of customers, in product development, and in the aging of physical and intangible assets. Learn how to model these challenges in class 6 of our online course. Followers get a 1/3 saving – enter coupon ‘blog33‘ at checkout.

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