Exercises: Model validation: Lean Startup

Explain what the Lean Startup methodology is and why it proposes validating ideas with real customers instead of blindly trusting the initial plan.

The basic Lean Startup cycle is build → measure → learn. Describe what is done in each phase and explain why it is a cycle and not a line that ends in 'launch'.

The diagram shows the Lean Startup validation cycle around the minimum viable product (MVP). Identify the missing phase, marked with '?', and explain what two decisions can come out of it.

A team wants to validate a book-swapping app for neighbors. Propose a minimum viable product (MVP) that does not require coding the full app (for example, a messaging group and a form) and explain what hypothesis it allows them to test.

In Lean Startup, after measuring, you must decide whether to persevere (continue improving in the same direction) or pivot (change strategy while retaining what was learned). Define both options and reason what you would do if data shows that many people try your recipe app, but hardly anyone uses it again.

Customer development recommends 'getting out of the building' to talk to customers before building anything. Explain how you would conduct ten interviews to validate a healthy snack box service and why questions like 'do you like my idea?' should be avoided.

A startup spent a year programming its online class platform without showing it to anyone 'so it wouldn't be copied', and upon launching discovered that students wanted something else. Diagnose which Lean principles were violated and reconstruct what its first build–measure–learn cycle would have looked like if applied from the first month.

A startup's monthly report shows: 150,000 cumulative downloads (+25 %), 80,000 social media followers (+40 %), weekly retention rate of 2.3 % (-15 %), and free trial to paid subscription conversion rate of 0.8 % (-0.5 points). The marketing director proposes doubling advertising spend, arguing that "the business keeps growing." Technically refute her proposal based on the analysis and interpretation of these data, classifying and justifying each metric according to its methodological typology (vanity or actionable metric), and predict what will happen to the company's financial viability if they maintain this strategy.

Design a complete validation experiment for a healthy office meal delivery service: state the main hypothesis, the MVP you would use, the metric you would measure, and the numerical criterion you would use to decide whether to persevere or pivot. Justify each choice.