Research issues

• extraneous variables are any variable other than the IV that may affect the DV if not controlled. They are nuisance variables that do not vary systematically with the IV.
• confounding variables are variables that systematically vary with the IV. They act as another IV that can be the main cause for the DV.
• demand characteristics are any cue the researcher or research situation might give which makes the participant feel like they can guess the aim.
• investigator effects are any unwanted influence of the researchers behaviour on the DV. The behaviours may be conscious or unconscious .
• Randomisation is the use of chance methods to control effects of bias when designing materials and order of conditions.
• Standardisation is using exactly the same formalised procedures and instructions for all participants in a research study.