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Menu engineering: the Kasavana & Smith method explained
Menu engineering ranks each dish on a menu by popularity and unit margin. A dish is popular when its share of sales reaches 70% of the average share; it is profitable when its margin is above the sales-weighted average margin. This gives four classes: STAR, PUZZLE, WORKHORSE and DOG.
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The two axes of the matrix
- Share of sales: portions sold of the dish divided by the total portions sold of the dishes analysed.
- Popularity threshold: 70% of the average share, that is 0.7 multiplied by 1 divided by the number of dishes.
- Unit margin: average selling price excluding tax minus the ingredient cost of the portion.
- Sales-weighted average margin: sum of margins multiplied by portions sold, divided by total portions.
The method, published by Michael Kasavana and Donald Smith in 1982, works with margin in XPF rather than food cost percentage: a dish with a high food cost can earn more than a dish with a low one.
The four classes and the related action
| Class | Popularity | Margin | Action |
|---|---|---|---|
| STAR | high | high | keep and feature |
| PUZZLE | low | high | promote or reposition |
| WORKHORSE | high | low | optimise the cost or adjust the price |
| DOG | low | low | rethink or remove |
The matrix informs the decision without replacing it: a DOG dish can stay on the menu if it plays a role, such as a kids' dish or a signature dish.
Example with a four-dish menu
| Dish | Portions sold | Share of sales | Unit margin | Class |
|---|---|---|---|---|
| Poisson cru (raw fish salad) | 40 | 40% | 1,500 XPF | STAR |
| Grilled mahi mahi | 10 | 10% | 1,800 XPF | PUZZLE |
| Burger | 35 | 35% | 900 XPF | WORKHORSE |
| Mixed salad | 15 | 15% | 700 XPF | DOG |
What Rongo does
Rongo applies this rule to sales by outlet imported from the POS and to the ingredient cost of each recipe card, by period and by service. Rongo imports Excel export files from your ERP and your POS: there is no real-time connection to these tools.
Frequently asked questions
Why a 70% popularity threshold?
It is the rule proposed by Kasavana and Smith: a dish counts as popular when it reaches at least 70% of the share it would have if sales were spread evenly across all the dishes analysed.
Should I reason in margin or in food cost?
In unit margin, in XPF. Food cost percentage remains useful to monitor a dish, but the matrix compares what each dish actually earns with the sales-weighted average margin.
Which dishes should be analysed together?
Comparable dishes: the same category, the same outlet and the same period. Mixing starters, desserts and drinks distorts the average share and therefore the popularity threshold.