Famous advice, tried on real businesses.

The Lean Startup: MVP and build-measure-learn

Eric Ries — The Lean Startup (book, 2011)

Eric Ries: Wrote The Lean Startup and founded the Long-Term Stock Exchange.

“The fundamental activity of a startup is to turn ideas into products, measure how customers respond, and then learn whether to pivot or persevere.”

Run a startup as a series of experiments: build the smallest product that can test a key assumption, measure how real customers behave, and use what you learn to decide whether to change course or carry on. Progress is counted in validated learning, not features shipped.

When it applies: Your business idea rests on untested assumptions about who will use or pay for it.

Customer development: get out of the building

Steve Blank — The Four Steps to the Epiphany (book, 2005)

Steve Blank: Serial entrepreneur and Stanford adjunct professor who created 'customer development', the root of Lean Startup.

A startup is not a small version of a big company: alongside building the product it needs a parallel process for finding and proving its customers, done by leaving the office and testing assumptions with customers directly. Blank's four steps are customer discovery, customer validation, customer creation and company building.

When it applies: You are about to commit to building or selling on assumptions about customers that nobody has checked with actual customers.

The Mom Test: ask about their life, not your idea

Rob Fitzpatrick — The Mom Test (book, 2013)

Rob Fitzpatrick: Founder who wrote The Mom Test, a guide to honest customer conversations.

People are polite about your idea, so their opinions and promises are poor evidence. Ask about their real behaviour and specific past events instead of pitching, avoid hypotheticals about the future, listen more than you talk, and treat concrete commitments such as time, money or introductions as the real signal.

When it applies: You are interviewing or emailing potential customers to decide whether an idea is worth building or selling.

Product/market fit is the only thing that matters

Marc Andreessen — The only thing that matters (Pmarca Guide to Startups, part 4) (post, 2007)

Marc Andreessen: Co-created Mosaic, the first popular web browser, and Netscape; co-founded Andreessen Horowitz.

“Product/market fit means being in a good market with a product that can satisfy that market.”

Of team, product and market, the market matters most: a strong market pulls a product out of a startup, while a weak one defeats even a great team. Until you reach product/market fit, do whatever it takes to get there and largely ignore everything else.

When it applies: You have not yet seen clear signs that customers are pulling the product from you (word of mouth, fast-growing usage, sales closing easily).

Argues against: The Four Fits: market, product, channel and model must line up

Sean Ellis's 40% 'very disappointed' test

Sean Ellis — When Should a Startup Start Charging? (definition first given in 'The Startup Pyramid') (post, 2009)

Sean Ellis: Ran early growth at Dropbox, LogMeIn and Eventbrite; coined the term 'growth hacker'.

“at least 40% of your active users saying they would be “very disappointed” if they could no longer use your product”

Ask active users how they would feel if they could no longer use the product. If at least 40% say 'very disappointed', you probably have product/market fit and can push on growth; below that, keep working on the product. Ellis himself calls the cut-off somewhat arbitrary, drawn from comparing dozens of startups.

When it applies: You have active users and need to decide whether to keep improving the product or start investing in growth.