Experiments/quasi-experiements

• Experiments; A research method where the researcher manipulates the IV in order to measure the effect on the DV

  Main features;

  • Deliberate manipulation of operationalised IV
  • Experimental and control condition
  • Researcher allocates ppts
  • Aim is to establish cause and effect
• Experiments;

  +Increases validity, manipulates IV to suit study, control EV and establishes cause and effect

  +Easily repeated, control over IV, controlled environments, increases external reliability

  -Lowers internal validity, if know they are in experiment, chance of demand characteristics, change behaviour to help/hinder

  -Artificially manipulating the IV, controlled environments, not true life reflection, lowers ecological validity
• Quasi-Experiments; A research method where the IV changes naturally, not manipulated by a researcher, DV is still measured

  Main features;

  • Researching naturally changing IV
  • Effect on DV of changing IV measured
  • Natural experiment or difference study
  • Researcher has no control over allocating ppts
• Quasi-Experiments;

  +Can research broader range of behaviours where it may be impractical/unethical to manipulate IV

  +Increases ecological validity, investigating naturally changing IV, measure DV in natural environment

  -Difficult to establish cause and effect as researcher doesn't manipulate IV, doesn't control for EV

  -Lowers external reliability, natural experiments cannot be repeated due to no control of IV and EV