Independent groups design

• You have a different group of people who each perform only one condition of the IV. The scores of the group who complete one condition are compared to the other group in the other condition
• (+) Reduction in demand characteristics- because participants only see one condition so cannot guess aim as easily.
• (+) No order effects – there is no practice or fatigue because participants are only tested once.
• (-) There are more likely to be participant variables – differences in people that can explain results other than IV.
• (-) More participants are needed than in a repeated measures design.
• Dealing with participant variables in

  an independent groups design

  Random allocation

  If using an independent groups you should use random allocation. It means putting your participants into which condition they will be doing RANDOMLY.

  Q: Why would this be important?

  It minimises the chance of having any bias in deliberately picking people to do a particular condition.

  It minimises the chance of participant variables affecting the study as it (theoretically) distributes participant variables evenly.