Control of Variables

• Extraneous variable


  A variable which might interfere with the DV
• Confounding variable


  A variable which has definitely interfered with the DV and confounded the result
• Situational variables


  Stem from aspects of the environment where the study is conducted
• Participant variables

  Stem from the ways in which participants differ from each other
• demand characteristics


  Participants try and work out what is going on in an experiment
• Investigator effects


  Any effect that the investigator's behaviour (conscious/ unconscious) has on the research
• Randomisation


  Refers to the use of chance to reduce the researcher's influence on the design of the investigation
• Standardisation


  Refers to using the same procedures and instruction for all participants in a research study