The problem it solves
In a company without S&OP, several plans coexist without ever meeting. Sales has its target. Operations has its production plan. Finance has its budget. All three cover the same products and the same months, and all three give different figures.
Nobody is wrong: each function plans on its own assumptions, for its own use. But the gap only shows up at the moment it costs something — a stockout, dead inventory, or capacity paid for nothing. S&OP exists so that the gap is dealt with beforehand, in a meeting, rather than afterwards, in a warehouse.
The cycle, in five steps
The cycle is typically monthly, and always in the same order. That regularity is where its value comes from: everyone knows when their subject will be handled, so nobody needs to force it through as an emergency.
1. Data gathering
Actual sales for the closing month, gap against the previous forecast, inventory levels, order book. You look at what happened before discussing what will happen.
2. Demand review
Sales and marketing build the demand forecast by product family. It includes launches, promotions and known commercial decisions. It is an unconstrained forecast: what we expect to sell, without yet asking whether we can make it.
3. Supply review
Operations and procurement compare that demand with real capacity: machines, labour, materials, supplier lead times. They produce a feasible plan, and above all the list of points where demand does not fit.
4. Pre-S&OP — reconciliation
This is the step that does the most work, and the most exposed one when the calendar tightens. It handles the gaps between demand and supply, prepares costed scenarios, and escalates to the executive team only the trade-offs that genuinely concern it.
5. Executive S&OP
Leadership settles what could not be settled, and signs off a single plan. That plan becomes the reference for everyone until the next cycle — which is what separates S&OP from a status meeting.
Horizon and granularity
Two characteristics separate S&OP from operational planning. Confusing them is enough to drain the process of its point, for the reason given under each.
- The horizon is long — typically eighteen to twenty-four months. Long enough that capacity, hiring and supplier contract decisions can still be taken in time. A three-month horizon leaves no lever open at all.
- The granularity is aggregated — by product family, not by item. Aggregation reduces relative forecast error: a family can be forecast with acceptable accuracy, where a single item is far less reliable. Going down to item level in S&OP means spending the meeting arguing about statistical noise.
S&OP, MPS, IBP: who does what
- S&OP decides volume, by family and over two years: how much we sell, how much we make, how much we hold.
- MPS — the master production schedule — turns those volumes into quantities per item and per short period. It executes what S&OP decided; it does not reopen the discussion.
- IBP — Integrated Business Planning — extends S&OP to the financial plan and to projects. Same cycle, same meeting, but the plan comes out costed in money as well as in units.
Why it fails
Four causes of failure follow directly from what precedes, and none of them are technical:
- Leadership does not attend. Without executive arbitration the meeting cannot settle anything, and reverts to a review of indicators.
- It drops into detail. The discussion slides towards this week's orders, and the long horizon — the only one where levers still exist — is never reached.
- Everyone keeps their own number. If sales leaves with its target and operations with its plan, S&OP produced a meeting, not a decision.
- Forecast accuracy is never measured. Without tracking the gap, nobody learns, and the same optimism returns every month.
Where to start
S&OP is not rolled out across the whole portfolio at once. The order below is not a standard: it is the one that exposes the process least to the four causes of failure above.
- Pick one family, and only one. The one whose gaps hurt most, not the easiest one. The process has to prove its value where the problem is visible to everyone.
- Fix the calendar before the content. The five steps, on the same dates every month, with the same people. A process whose date is negotiable does not exist.
- Accept imperfect data in the first cycle. Waiting for clean master data before starting means never starting: it is the meetings that reveal which data deserves to be cleaned up.
- Measure forecast accuracy from month one. It is the only indicator that makes the demand review improve, and the only one that stops the same optimism returning unnoticed.
- Write the decisions down. One line per trade-off, with its owner and its date. That is what separates, at the next cycle, a decision from a memory.
Extending to other families comes afterwards. The signal is not a duration but an observable fact: the cycle runs without having to be chased.
Making it land with the people in the room
The difficulty of S&OP is not understanding the process — it fits on one page, this one. It is accepting that a decision which is locally sub-optimal for your own function can be the right one for the company. That is not something a slide deck demonstrates.
It is what the S&OP Game stages: each participant holds one link, optimises it, and discovers at the debriefing the cost their trade-offs imposed on everyone else. The demonstration takes half a day and is not open to argument — the figures are the room's own.