Separate uplift from coincidence

Show a baseline bridge

A promotion plan starts with demand expected without the event and adds an explicit incremental effect. Northstar baseline forty with a twenty-five-percent uplift gives fifty. Keep the ten-unit addition separate. Record dates, price, channel, displays, distribution, and whether the affected customers already appear in the baseline or firm orders.

A promoted week of seventy versus normal forty does not prove thirty incremental units caused by promotion. Distribution, weather, holidays, or stock availability may also change. When events always occur together, the data may not identify their separate effects. Describe what the comparison shows without claiming more than the evidence supports.

Inspect controls and spillovers

Suppose a promoted region rises from forty to seventy while an untreated region rises from thirty to forty-five. Changes are thirty and fifteen, leaving a difference in changes of fifteen. A causal interpretation requires comparable untreated trends and no other unequal shocks. One before and one after observation cannot establish those assumptions.

Promotions can pull demand from later weeks or shift customers between Northstar SKUs. Inspect the event window and follow-up weeks at both product and company levels. A large uplift on one SKU can coexist with a small company increase. More units also need not mean higher margin; commercial evaluation requires its own price and cost inputs.

Keep uncertainty explicit

Use conditional cases when evidence is limited. Baseline forty plus uplift assumptions zero,ten,twenty gives forty,fifty,sixty. These are not automatically probability intervals. State what would make the high case plausible, such as verified extra stores. Do not average scenarios into an expected value unless defensible probabilities are supplied.

Afterward, preserve the original forecast and record whether the offer actually ran as planned. Stockouts can hide demand during the event. Separate execution differences, measurement limits, and forecasting error. Replacing an original uplift with the observed difference destroys the record needed to learn whether the adjustment process helped.

Build, test and explain a plan

Six weekly A baselines are forty each. Promotion weeks three and four add ten each in the base case; week five loses six to pull-forward. B baseline twenty each; B loses three in each promotion week. No other changes. 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.

Your deliverables

• Auditable input and formula model with checks
• Scenario comparison and annotated chart
• Decision memo, correction log, and teach-back notes

Keep these three ideas

• Build promotion scenarios without treating a before-after difference as causal proof.
• 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.