Research issues

Question 1

Extraneous variable (EV)

Answer 1

Any variable, other than the independent variable (IV), that may affect the dependent variable (DV). EV’s are essentially nuisance variables that do not vary systematically with the IV.

Question 2

Examples of extraneous variables

Answer 2

The age of the participants or the lighting in the lab.

Question 3

Confounding variables

Answer 3

A kind of EV but the key feature is that a confounding variable varies systematically with the IV. Therefore we can’t tell if any change in the DV is due to the IV or the confounding variable.

Question 4

Demand characteristics

Answer 4

Any cue from the researcher or from the research situation that may be interpreted by participants as revealing the purpose of an investigation. This may lead to a participant changing their behaviour within the research situation. May be a please-U effect or a screw-U effect.

Question 5

Investigator effects

Answer 5

Any effect of the investigators behaviour (conscious or unconscious) on the research outcome (DV). This may include everything from the design of the study to the selection of, and interaction with, participants during the research process.

Question 6

Randomisation

Answer 6

The use of chance methods to control for the effects of bias when designing materials and deciding the order or experimental methods.

Question 7

Standardisation

Answer 7

Using exactly the same formalised procedures and instructions for all participants in a research study.