Research issues

• Extraneous variables

  Any other unwanted variables that might potentially interfere with the IV. Many are easy to control (e.g. lighting in a lab). These are called nuisance variables. They do not confound the findings of the study, just make it harder to detect a result.
• Confounding variables

  A type of EV that changes systematically with the IV. They make it hard to tell whether the IV or the confounding variable is acting on the DV.
• Demand characteristics


  In the research situation, participants will try to figure out what is going on. Demand characteristics are the clues (or cues) that help participants identify what the purpose of the study is. They may then act how they think is expected to please the experimenter (‘please-U effect’) or deliberately sabotage the results (‘screw-U effect’).
• Investigator effects

  The effect of the investigator on the participants. This can be any unwanted influence of the investigator on the research outcome. Coolican (2006) states this can include expectancy effects and unconscious cues. It might also refer to any actions of the researcher that were related to the study's design, such as the selection of the participants, the materials, the instructions, etc. Leading questions are a good example.
• Randomisation

  The use of chance methods to control for the environment effects of bias when designing materials and deciding the order of experimental conditions e.g. names out of a hat, using a computer etc
• Standardisation

  Using exactly the same formalised procedures and instructions for all participants in a research study. Ensures that changes in procedure do not act as extraneous variables.