Start with something familiar
For a picnic, a normal guest count, confirmed extra guests, and visitors who come only in good weather are different inputs. Averaging everyone's guesses does not reveal whether the same visitors appear twice. A useful discussion identifies each group and its attendance condition. Demand consensus similarly clarifies evidence and ownership. Agreement on a number is less useful if nobody can say what changed or what would make the group reconsider it.
Words to know: Scenario, Forecast consumption, Demand.
Begin with a common baseline
Bring one dated baseline and an adjustment register. Northstar baseline forty-five plus six genuinely incremental new-store units gives fifty-one. An existing order of ten already inside baseline adds zero. A sales target of sixty-five is a goal, not evidence that customers will request sixty-five. Keep the gap visible without forcing the forecast upward.
Each adjustment needs an owner, evidence date, affected product and period, incremental quantity, and expiry condition. An adjustment should not persist forever because its origin was forgotten. Preserve baseline and final versions so future review can evaluate whether judgment helped on the same frozen target and lead time.
Tie scenarios to conditions
An optional event adds twelve only if it occurs, making event-on demand sixty-three from a base of fifty-one. A downside loss of eight gives forty-three. These cases help prepare responses; they are not calibrated intervals and carry no probability unless evidence supports one. Do not call their average expected demand without probabilities.
Avoid stacking adjustments that represent the same cause. More stores and more display exposure may overlap. Explain which assumptions move together and which are separate choices. Timing matters as much as a total: shifting an event between weeks can preserve monthly volume while moving the operational peak beyond available capacity.
End with a decision record
Consensus is a working assumption with accountable owners, not certainty. Record disagreements and evidence that would resolve them. Sales can verify the store opening, the analyst can preserve the baseline, and a review chair can approve the published version. End with actions, dates, and triggers rather than a vague request to revisit the forecast.
When outcomes arrive, compare baseline and adjusted errors and record whether the planned event happened. A reasonable forecast can still be wrong; a lucky forecast can rest on weak evidence. Learning requires keeping the original reasoning and distinguishing changed execution from a poor estimate of the demand effect.
- Define target
- Check evidence
- Calculate
- Challenge assumptions
- Record decision
Run an evidence-based demand review — worked case
All inputs below describe fictional Northstar bottles. Keep the stated units and timing when reproducing the calculation.
| View | Calculation | Demand |
|---|---|---|
| Base | 45+6 | 51 |
| Downside | 51-8 | 43 |
| Event on | 51+12 | 63 |
- 1. Add only six incremental store units.
- 2. The included order adds zero.
- 3. Publish event and loss conditions separately.
Base 51, downside 43, event-on 63; target 65 remains a goal.
Assumptions
- Periods and quantities use the definitions stated in this example.
- Only explicitly supplied events or adjustments are included.
Where this can fail: The arithmetic checks the stated assumptions; it does not establish that uncertain future events will occur.
Build, test and explain a plan
Four-week baselines [45,48,47,50]; incremental new-store units [6,6,8,8]; included orders [10,12,10,14]. Optional event adds twelve in week two. Downside loss removes eight in weeks three and four. Targets are sixty-five every week. All units are bottles unless stated otherwise. Use a spreadsheet or ruled paper. Eight hours includes construction, comparison, writing, and teach-back; this is a planning estimate, not an experimentally validated completion time.
Use paper or a spreadsheet. The estimates below include the study and worked example already on this page.
| Estimated hours | Activity |
|---|---|
| 0.5 | Study the lesson and write a data dictionary defining every field, time bucket, unit, and cutoff. Separate observed facts from assumptions. Identify two ways a colleague could misread the target and rewrite its definition to prevent those errors. |
| 0.5 | Reproduce the worked example independently, showing formulas and intermediate values. Compare against the answer and keep a correction log explaining each difference. Check one result a second way using a total, balance, or direct manual calculation. |
| 3 | Build an adjustment register and base,event-on,downside,combined scenarios. Separate each driver and identify an evidence owner, cutoff, and expiry rule. Prepare a review agenda that resolves overlap. Keep inputs separate from formulas, label every origin and target, and add independent row and total checks. Produce an annotated chart with at least two observations tied to specific rows; include a brief explanation of why each check matters. |
| 2 | Move the event from week two to week three. Separately delay the store, changing additions to [0,6,6,8]. Compare targets without converting target gaps into demand adjustments. Preserve each variant separately. Create an output comparison table and explain which changed assumption caused each movement. Identify a scenario that affects timing differently from totals and state what the planner should do with that distinction. |
| 1 | Write a 400-word decision memo using your own numerical outputs. State the proposed action, evidence, two limitations, an owner for the next check, and a measurable condition that would change your recommendation. Attach the model so a reader can audit every cited value. |
| 1 | Prepare a five-minute teach-back using one worked row and one scenario comparison. Explain it aloud to a colleague or recording. Write three skeptical questions, answer them with evidence, and revise the memo or model where your explanation exposes an unsupported assumption. |
Your deliverables
- Auditable input and formula model with checks
- Scenario comparison and annotated chart
- Decision memo, correction log, and teach-back notes
Check your practice work
- Base [51,54,55,58], total 218; orders add zero.
- Event-on [51,66,55,58], total 230; downside [51,54,47,50], total 202.
- Combined [51,66,47,50], total 214.
- Event shifted [51,54,67,58], still total 230 but peak moves.
- Late-store base [45,54,53,58], total 210. Target total 260 exceeds original base by 42.
Keep these three ideas
- Keep baseline, approved adjustments, targets, and conditional scenarios distinct.
- Keep original evidence distinct from modeled values and assumptions.
- A precise output remains conditional on definitions and timing.
Common mistakes
- Overwriting the original evidence after a revision.
- Reporting a number without its unit, period, cutoff, and assumptions.
Optional video study
Keep baseline, approved adjustments, targets, and conditional scenarios distinct.
- Begin with a common baseline
- Tie scenarios to conditions
- End with a decision record
One half of the module narration, with a distinct Northstar calculation and a bridge to the paired lesson.
Open the module media & quizPut this idea to use
Carry your assumptions into a practical tool, then compare your result with a short guide.
Open a related planning toolRead the related planning guidePractice with the planning gameThis saves a completion marker in this browser only. It does not verify time spent.