Updated October 2026. Lean Startup principles corrected against theleanstartup.com; 2014 BlackBerry app promo removed.
Most founders know they should test an idea before they build it. Eric Ries's Lean Startup method, as published on the Lean Startup principles page, names five principles: entrepreneurs are everywhere, entrepreneurship is management, validated learning, innovation accounting, and build-measure-learn. The practical warning on that same page is the one that still matters here. Too many startups spend months perfecting a product without showing even a rough version to a prospective customer.
The 2014 post turned that warning into four working rules.
- Start by searching for product-market fit.
- Get out of the building and talk to customers.
- Run a series of experiments to test your ideas.
- Test the thinking before you spend heavily. Do not build for months, or spend millions, before customers have seen the idea.
Many founders find it hard to reach real customers. Feedback from co-founders, friends, a small focus group, a user test, or even people who already buy from you can show how others see the offer. That sample is often too small, and it leans towards people who will be polite, or who have already said they like the product.
Check the idea with a sample that matches the target group, meaning the people you hope will become customers. For a more detached read of the same questions, a firm can commission an outside team to gather and analyse the data. That is the work described on our data collection in Jamaica page.
Updated October 2026
- The four bullets are kept as the post's working rules. They are no longer described as the Lean Startup principles. The five principles are quoted from theleanstartup.com/principles.
- The BlackBerry App World download line was removed. It was a 2014 app promo, not part of the argument.
- The old link to a "research outsourcing" page now points to /data-collection-jamaica/.