DevelopModellingPlatform-enabled

Sharing Ratio

The evidence-based determination of desk and setting sharing — derived from workforce demand, attendance rhythm and peak structure, with its risk scenarios and change implications made explicit.

What sharing ratios does this organisation's measured demand and rhythm actually support — per population, at what risk, with what change cost?
Why this matters

The sharing ratio is the most consequential number in most workplace strategies and the most frequently guessed. It determines capacity, cost, experience and change intensity simultaneously — and when it is imported from a benchmark rather than derived from this organisation's measured rhythm, it fails in one of two expensive directions: wasted capacity or Tuesday crisis. This method derives the ratio from evidence, differentiates it where the evidence differentiates, stress-tests it against risk scenarios, and prices its change implications honestly.

When to use it
  • In Develop, once the concept direction is set and the presence logic is decided
  • Whenever a benchmark ratio ('everyone does 0.7 now') enters the room and needs replacing with evidence
  • Re-run in Recalibrate when attendance assumptions breach their triggers
Who should participate
  • Strategist and spatial analyst running the model
  • CRE and Finance for capacity and cost consequences
  • HR and change lead for the change implications
  • Team leads of populations at differentiated ratios — they must understand and be able to explain their number
Inputs
  • Presence logic and rhythm redistribution from Hybrid Balance
  • Temporal rhythm model: daily curves, weekly structure, demand cliffs
  • Peak occupancy structure from the Occupancy Assessment
  • Ratio bands and population differentiation from Taxonomy Alignment
  • Dedicated-setting requirements: roles, equipment or regulation demanding assigned positions
What happens
  1. Model workforce demand against the rhythm structure: not average attendance, but the distribution of simultaneous presence per population per day type.
  2. Derive the ratio per population from peak structure with an explicit service level: what percentile of demand days does the capacity serve, and what happens on the days beyond it?
  3. Separate dedicated from shared settings on evidence: which roles hold requirements (equipment, regulation, continuous presence) that assignment genuinely serves — and which hold history.
  4. Stress-test against risk scenarios: the all-anchor-day collision, the post-policy attendance rebound, the growth scenario's headcount, the seasonal peak. Record where each ratio breaks and what the overflow protocol is.
  5. Model the interaction with rhythm redistribution: a ratio that fails under current anchor days may hold under the redistributed rhythm Hybrid Balance designed — the ratio and the rhythm are one system.
  6. Price the change implications per ratio step: the behavioural distance between 1:1 and 0.8 is small; between 0.8 and 0.6 it is a different workplace. Change cost is part of the ratio decision, not a footnote.
  7. Document each ratio with its evidence chain, service level, break conditions and overflow protocol; register the attendance assumptions in Calibration.
What to look for
  • Average-based ratios that die on Tuesdays — the peak distribution, not the mean, sets the number
  • Dedicated-desk claims that are seniority in requirement costume
  • Ratios tightened to make a business case close, with the experience cost booked to nobody
  • Uniform ratios flattening evidence-based differentiation for administrative comfort
  • Overflow protocols that don't exist: every ratio has break days, and pretending otherwise converts a known condition into a crisis
Outputs
  • Evidence-derived sharing ratios per population with service levels
  • Dedicated-versus-shared setting register with evidence per dedication
  • Risk scenario results and break conditions per ratio
  • Overflow protocol
  • Change implication assessment per ratio step
  • Registered attendance assumptions with triggers
How the output is used

The ratios drive capacity in Stacking and Blocking and setting quantities in the Kit of Parts. The change implications enter the Deliver-phase change programme. The registered assumptions and break conditions become Recalibrate's monitoring targets: when observed attendance breaches the trigger, the platform regenerates the ratio model rather than the organisation discovering the breach through Tuesday queues.

Human judgement required

The model produces the distribution; judgement sets the service level — how many break days per year the organisation accepts is a leadership decision about cost versus experience, not an output. So is the call on which dedication claims are genuine and which are status, a judgement requiring political courage the arithmetic cannot supply.

Common mistakes
  • Importing a benchmark ratio and reverse-engineering the justification
  • Modelling on average attendance
  • One ratio for all populations against differentiated evidence
  • Deciding the ratio without pricing its change distance
  • No overflow protocol, so the first break day becomes the ratio's public failure
Practical example

A consultancy's finance team demanded 0.6 across 1,400 staff to close the business case. The peak-distribution model showed 0.6 breaking 47 days a year for client-facing teams under their required overlap rhythm — but holding at 11 break days under the redistributed rhythm, with a defined overflow protocol into bookable project space. The decision became explicit: 0.6 with rhythm redistribution and overflow provision, accepted by leadership with the break-day count on the record. Observed break days in year one: nine.

45 methods in the library.