I finished reading That Will Never Work, the biography about Netflix’s early years. Cofounder and first CEO Marc Randolph’s perspective on taking the company from idea to IPO in seven years is full of wisdom that entrepreneurs will find helpful.

One of his principles I enjoyed was what Marc and Reed Hastings call the “Canada Principle.” For the first twelve years, Netflix served only the United States. But several times during that period, they thought about expanding into Canada. It was close, so shipping costs would be low (it was shipping DVDs then), and the regulatory environment was friendly. Canada looked like low-hanging fruit.

But first appearances were deceiving.

When they dug into it, they learned it would be complicated:

• French is the main language spoken in some parts of Canada, so they’d have translation issues.
• Canadian dollars differ from U.S. dollars, so they’d have to deal with currency issues.
• The postal system in Canada was different, so special envelopes would be necessary.

When they ran the numbers, they learned they’d get a roughly 10% revenue boost by expanding into Canada.

They then considered the “effort, manpower, and mind-power” required to expand into Canada. It would be a big lift for their team. Then they analyzed how much they could increase revenue if they applied the same amount of effort to other aspects of the business.

Using that framework to evaluate the decision made things crystal clear. If they applied that effort in other areas, they could get a far greater return by increasing revenue considerably more than 10%. Expanding into Canada wasn’t the best way to allocate their resources. The return was too low relative to other options requiring similar effort.

They realized that Canada was a short-term, obvious move that would provide short-term benefits. “It would have diluted our focus,” wrote Marc.

After this experience, Netflix adopted what Marc calls the “Canada Principle.” When faced with options, evaluate the potential return of each of them and the effort and resources required to generate it. Pick the highest-return activity and focus on it. Don’t spread yourself thin and lose focus by doing low-return activities.

Marc and Reed realized, through trial and error, that focus is a superpower and that if they could focus on the right high-return activities, they’d have a competitive advantage. The Canada Principle became key to deciding what initiatives to pursue or kill.

The Canada Principle led the company to stop selling physical DVDs and focus entirely on subscription rentals, even though DVD sales were 90% of their revenue. It also helped them decide against pursuing automated DVD rental kiosks, despite promising results from months of testing. (Side note: a team member on the kiosk project helped found Redbox.) All of these were the right decisions. They kept the company focused. They leapfrogged competitors and built a behemoth that’s now publicly traded and has a market capitalization (valuation) of over $410 billion as of this writing.

I didn’t have a name for it when I was building my company, but I applied the Canada Principle several times when making strategic decisions. It was sometimes painful in the short run, but it usually led to the best long-term decision.