pilot studies and experimental design

• what is a pilot study?

  • a small scale study which takes place before the real study to to find out if there is any problems with:
  • experimental deign-do partcipants have enough time to complete tasks?
  • instructions for participants-are the instructions clear?
  • measuring instruments- including behavioural categories and questions
• experimental design

  3 types of experimental design are:

  -repeated measures

  -independant groups

  -matched pairs
• repeated measures

  • design where the same participants take part in each condition and the data is then compared for each participant to see if there was a difference
• evaluation of repeated measures

  +fewer participants are required making the design less time consuming and expensive

  -order effects can occur if same participants are taking part in both conditions
• independant groups

  • uses two separate groups of participants (one group in each condition)
  • participants are allocated their condition randomly to ensure each participant has equal chance of being assigned to each group
• evaluating independent groups

  +avoids order effects as people only have to take part in now condition, they don't become as bored

  -participant variables may effect results e.g. differences in age, gender or social background affect results as acting like a DV so psychologists can't be sure the IV caused the damages measured
• matched pairs

  • pairs of participants are matched from the sample in terms of variables (age or IQ)
  • one member of each pair is placed in the experiment group and the other member in the control group
• evaluating matched pairs

  +order effects are less likely as each participant only takes part in one condition

  -more expensive and time consuming than repeated measures