Analytic Lessons from Subway’s $5 Footlong Promotion

Subway’s $5 footlong promotion has become a nationwide hit. In “The Accidental Hero,” BusinessWeek writer Matthew Boyle describes how the promotion grew from just a few franchises in Florida to become a top-10 fast-food brand this year. The story demonstrates how a small, local idea can become a nationwide success. The story also powerfully displays some key analytic lessons on the application and use of demand elasticity and controlled experiments to improve business performance in a sustainable way.

Demand Elasticity
Subway’s $5 footlong promotion was so popular, so fast, that it caused inventory shortages throughout the company. This surge in sales volume generated more revenue AND profits starting with the pioneering franchise: “…food costs did rise as a percentage of sales, but that was offset by the overall boost in volume and the increased productivity of …employees, who had less down time. Even after adding two new staffers, [franchisee] Frankel made money on each $5 sandwich.”

In other words, the footlong sandwich used relatively more expensive food than the typical sandwich, but sales volumes increased the proportion of time employees spent making sandwiches versus standing idle. The biggest bonus likely came from the incremental demand created by the promotion. The new demand created by the promotion directly added to revenues and profits. The lower pricing brought new customers to stores and (presumably) encouraged existing customers to buy more sandwiches. Subway discovered that these sandwiches have very high demand elasticity (for reasons described in the article), meaning that the percentage increase in demand was very high relative to the percentage change in price. The menu of higher pricing had prevented Subway from tapping into a hidden reservoir of demand. (Note that food service consultant Dean Dirks speculates that Subway’s promotion is actually a money-loser).

Controlled Experiments
Subway managed to execute this powerful pricing concept without analyzing past transaction data. Instead, Subway used the more direct approach of controlled experimentation.

Controlled experimentation allows a business to try out an idea in a well-defined place and time. This setup facilitates convenient data collection and fast analysis of the data. If the idea works in the controlled setting, then expand the trial into a slightly larger controlled setting. Repeat the process until the recipe for success (or failure) appears sufficiently confirmed and understood.

In Subway’s case, the numbers spoke loud and clear. Profits and revenues soared for Frankel soon after launching the promotion at his two franchises in Miami. It ran for a year before it was tried at another Florida location, this time in Ft. Lauderdale: “On the first day of the promotion, the store nearly ran out of bread and meat. Sales doubled.” Next, the promotion expanded throughout South Florida and met more success. Despite this winning record, Subway’s franchisee marketing board still voted down a proposal to expand the promotion nationwide. Additional successes from “Washington to Chicago” finally convinced the board to approve nationwide expansion.

Key Lessons
The article does not count how many controlled experiments Subway has run in the past that began successfully and yet ended in failure. We also do not know how many “bad” ideas the board must endure at every meeting. (Many stories about success in business suffer from “survivorship bias” where only proven winners make it to the front page and the losers of the past are long forgotten). However, a key lesson in this story is that ideas for change are strengthened when backed by evidence and data. Subway was fortunate to own an infrastructure conducive to running and maintaining controlled experiments and fortunate to stumble upon an idea whose success was so undeniable. Even if your business is not similarly fortunate, applying the lessons of pricing to demand and of generating evidence through experimentation will certainly drive measurable improvement in your business.