Promotion & Markdown Analytics: Lift, Cannibalisation & Profit

What you'll build

What you will be able to do

Each lab ends with a concrete result that you build yourself and the checker confirms, cell by cell.

• Estimate what Oat Granola would have sold without the promotion: a pre-period average, cleaned of a stock-out week and adjusted for season.
• Measure six spring promotions against their baselines: incremental units, lift %, the share of promo units you would have sold anyway, and the overall lift.
• Compare three discount depths for Coffee Beans: promo profit, baseline profit, incremental profit and the money given away on units you would have sold anyway.
• Build the classic break-even lift table for margins and discounts, then test a supplier's forecast for Dishwasher Tablets against the break-even volume.
• Follow a spaghetti promotion into the rest of the aisle: profit lost on substitute pastas, profit gained on sauce and parmesan, and the net effect on the category.
• Measure how much of the kitchen-towel lift was just shoppers stocking up: the dip after the promo, the pull-forward % and the net incremental units, then chart the weeks.
• Test five markdown levels for the garden lounger: sell-through, revenue, leftover stock sold to a clearance buyer and the gross margin of the whole stock, then chart margin against sell-through.
• Rank the eight promotions of Fernhill's 2026 calendar by ROI, find the best one, and see what the year would have earned without the loss-makers.