validity

• validity


  refers to whether something is true or legitimate

  internal validity is achieved if the experiment measures what it intends to measure

  external validity is achieved if the findings of research can be generalised to real-life situations
• types of external validity - ecological validity


  refers to the findings being generalisable to other real-life situations, lab experiments do not have ecological validity as they are so highly controlled they lack realism
• types of external validity - temporal validity


  if the findings can be generalised across time, i.e. will the findings still be valid in five years
• types of internal validity - face validity 


  measuring what it intended to measure, making sure they are not measuring demand characteristics
• improving validity - experiments

  a control group is used to see whether the independent variable influences the dependant variable

  can use single bind (the participants do not know which condition they are in) or double bind (neither participant or researcher know which condition they are in) procedures which will reduce the chance of demand characteristics and investigator effects

  using standardised instructions so participants in both conditions receive the same information in exactly the same format to reduce investigator effects
• improving validity - questionnaires

  include a lie scale to check the consistency of the participants responses, this is done by having two questions asking the same thing in a different way

  the participants know that their responses will be anonymous so are less likley to answer in a socially desirable way
• improving validity - observations

  to improve ecological validity conducting a covert observation where they researcher is not seen so the behaviour observed is natural and participants will not be acting in a way that is desirable for the study

  using behavioural categories where researchers will tick off behaviours when they are seen which helps with validity as reduced the chance of researcher subjectivity