types of experiment

• what is in a laboratory experiment

  • IV manipulation
  • extraneous variables are controlled
  • random allocation
• what is in a field experiment

  • IV manipulation
  • lack of extraneous variable control
  • may or may not randomly allocate
• what is in a natural experiment


  • IV manipulation - already exists e.g how long orphans stay in care would have changed anyway
  • extraneous variables - little to no control
  • no random allocation
• what is a quasi experiment


  • IV manipulation - already exists between people
  • no random allocation