Control variables

What are extraneous variables?

Variables (other than the IV) that may have an effect on the DV. These do NOT vary systematically vary with the IV

What are confounding variables?

Variables (other than the IV) that will have an effect on the DV. These DO systematically vary with the the IV. It provides an alternative explanation for your results.

What are participant variables?

Individual differences between participants that may effect the DV.

What are situational variables?

Differences in the experimental conditions that may effect the DV e.g temp, time of day, weather.

What are demand characteristics?

Any cues from the researcher/ research situation that may indicate the purpose of the experiment

What are investigator effects?

Effects of the investigator on the DV. This may be conscious or unconscious. E.g smiling at participants giving the correct answers or asking leading questions

What is randomisation?

Use of chance to reduce the researchers influence on the investigation. E.g order of words on list are random. Controls for investigator effects

What is standardisation?

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