Lean ?

• Trim the fat, validate and don't commit before action
  • Don't spend any resource before you know it's needed
  • Don't build app before you know there's a need for it
  • Build smaller version of features, get feedback → build the rest

Waterfall ?

• Make a big and complex plan ahead
• This is not evil and good to be implemented in some scenario
  • ex : high stake apps that cannot be developed incrementally

Agile ?

• Set of values to ensure lean development
  • Individual and interaction over tools and process
  • Working software over documentation
  • Customer collaboration over contract negotiation
  • Respond to change over follow plan