Blog · Territory, capacity and quota planning · FMCG and CPG brands
The complete promotional net lift calculation on one SKU at one retail account over sixteen weeks, small enough to check by hand: the eight pre-promotion weeks and their median as the baseline, the two promotion weeks and the gross lift, the four post-promotion weeks and the dip, net lift, trade spend, cost per net unit, the same mechanic at a second account for comparison, and the assertion that the account's weekly sell-out sums to the retailer's total, so a reader can reproduce every figure and then run it on their own sell-out files.
Net lift is a baseline, a gross lift and a dip, and on sixteen weeks of one SKU at one account every step can be checked. This page works the baseline, the lift, the dip, the net, the cost per unit, the comparison account and the assertion.
| Week | Sell-out | Window |
|---|---|---|
| 1 | 4,200 | Pre |
| 2 | 3,900 | Pre |
| 3 | 4,100 | Pre |
| 4 | 4,400 | Pre |
| 5 | 4,000 | Pre |
| 6 | 4,100 | Pre |
| 7 | 3,800 | Pre |
| 8 | 4,300 | Pre |
| 9 | 9,100 | Promotion |
| 10 | 9,000 | Promotion |
| 11 | 3,600 | Post |
| 12 | 3,700 | Post |
| 13 | 3,900 | Post |
| 14 | 4,000 | Post |
| 15 | 4,100 | Back at baseline |
| 16 | 4,200 |
Baseline = median of weeks 1 to 8 = median(3,800, 3,900, 4,000, 4,100, 4,100, 4,200, 4,300, 4,400) = 4,100
Gross lift = Σ (promo week − baseline) = (9,100 − 4,100) + (9,000 − 4,100) = 5,000 + 4,900 = 9,900 Dip = Σ (baseline − post week), floored at zero = 500 + 400 + 200 + 100 = 1,200 Net lift = 9,900 − 1,200 = 8,700 units
Trade spend on this promotion at R-1: $21,000.
Cost per net unit = 21,000 ÷ 8,700 = $2.41
| Element | R-2 |
|---|---|
| Baseline | 6,300 |
| Promo weeks | 13,400 and 13,300: gross lift 14,100 |
| Post weeks | 2,900, 3,100, 3,600, 4,100: dip 12,900 |
| Net lift | 1,200 |
| Trade spend | $34,000 |
| Cost per net unit | $28.33 |
R-2's shoppers bought a month's supply in two weeks and stayed home. On shipments, R-2 was the better promotion.
Σ accounts' weekly sell-out for the SKU = retailer's total per week
Week 9: R-1 9,100 + R-2 13,400 + others = the retailer's reported total for the SKU. Holds each week, or a missing account file is listed and that account's promotion is marked unmeasured.
Measured on shipments. R-2 shipped the most; the sell-in spike is the retailer stocking.
No post-window. R-2's net lift reads 14,100 and it gets next year's spend.
Baseline including a prior promotion. If week 3 had been a promotion at 8,000, the median rises to 4,150 and the lift understates.
Mean baseline. One odd week moves it; the median does not.
The same baseline, windows and arithmetic per account per promotion, from the weekly sell-out files and the calendar. Covirage runs it after every promotion. The promo lift guide covers the measure, and the weeks of cover guide covers what the promotion weeks look like in channel inventory.
Because one high or low week in the pre-window would set a mean baseline the account does not normally sell at. The median is the account's typical week, and the pre-window excludes any earlier promotion.
Until sell-out returns to baseline, capped at a stated number of weeks, here four. The dip is the shortfall below baseline in that window. An account still below baseline at the cap is flagged: the promotion may have pulled forward more than four weeks of demand.
Because the same mechanic produced a real lift at one and a pull-forward at the other, and trade spend next year goes where the net lift is. The second account's shipments during the promotion looked like the better result.