Research Methods

• What are extraneous variables?


  Any variable other than IV that may affect the DV if not controlled.
• What is a confounding variable?


  A type of EV however varies systematically with IV. So we cannot tell if any change in DV is due to IV or confounding variable.
• What are demand characteristics?


  A cue from researcher or research situation that may reveal purpose of the investigation which leads ppts to change behaviour to suit research situation.
• What are investigator effects?


  Any effect of investigators behaviour on the research outcome which includes the design of the study to selection and interaction with ppts.
• What is randomisation?


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

  Controls investigator effects.
• What is standardisation?


  Using the same formalised procedures and instructions for all ppts in a research study.
• What are the 3 experimental designs?

  • Independent groups design
  • Repeated measures design
  • Matched pairs design
• Explain independent groups design

  • 2 separate groups of participants
  • 2 conditions
  • Ppts only experience 1 condition
  • Performance of the groups is compared
• What is a strength of independent groups design?


  Order effects are reduced because ppts only have one situation, so are less likely to carry out demand characteristics.
• What are 2 limitations of independent groups design?

  Different ppt variables, so results may be due to ppt variables not the IV. This reduces validity of findings. Therefore random allocation is used.

  Less economical than repeated measures because there is twice as many ppts needed therefore increased time and money spent.
• Explain repeated measures design

  • All ppts experience both conditions
  • Difference in ppts ability compared
• What is a limitation of repeated measures design?


  Order effects, ppts may guess the aim of the study which leads to more demand characteristics. However this can be overcome by counterbalancing whereby half the ppts take part in condition a and half in condition b then swap.
• What is a strength of repeated measures design?

  Ppt variables are controlled so higher validity and fewer ppts needed so less time consuming when recruiting.
• Explain matched pairs design

  • Ppts are paired together on variables
  • One ppt from each pair allocated into different groups
  • this attempts to control confounding variables of participant variables
• What is a strength of matched pairs design?


  Ppts only take place in one condition so order effects are less. Meaning less demand characteristics.
• What is a limitation of matched pairs design?

  Matching may be time consuming and expensive if pre-test is required so less economical.
• Explain a laboratory experiment


  Experiment conducted in a highly controlled setting.
• What strengths are there of lab experiments?

  • High control over confounding variables and extraneous variables so we can assume any effect on the DV is as a result of the IV. Therefore we can be more certain about cause and effect relationships so it has high internal validity.
  • Replication is more possible, due to a high level if control which ensured extraneous variables are not introduced when repeating experiment
• What are limitations of lab experiments?

  • Lack generalisability, as may be artificial so ppts may behave in unusual ways therefore low external validity.
  • Ppts may be aware they are being tested due to the controlled environment therefore may carry out demand characteristic.
• What is a field experiment?


  When the IV is manipulated in a more everyday setting, So the researcher goes to the ppts everyday setting.
• What are the strengths of field experiments?

  • Hight mundane realism because the environment is natural. This may produce behaviour which is more valid and authentic as ppts are unaware they are being studied so high external validity.
• What are limitations of field experiments?

  • There is a loss of control over CV’s and EV’s therefore the cause and effect between IV and DV may be difficult to establish and replication may not be possible.
  • Ethical issues because the ppt isnt aware they are being studied and they cannot consent which may be seen as a lack of privacy
• What features do natural experiments have?

  The researcher has no control over the IV and cannot change it. The IV is natural
• What are strengths of natural experiments?

  • Provides opportunities for research which may not have been available for practical or ethical reasons such as the Romanian orphans.
  • High external validity as the experiments involve everyday life
• What limitations are there of natural experiments?

  • They are naturally occurring events that do not happen frequently therefore reducing the opportunities for research, this may also limit generalisation to other findings.
  • Ppts wont be randomly allocated to conditions therefore research may be unsure if IV does affect DV as lots of other things could have affected it.
• What is a quasi experiment?


  One in which the IV is based on an existing difference such as age or gender. The DV is naturally occuring or may be devised by experimenter in field or lab
• What are strengths of quasi experiments?


  They are carried out under controlled conditions so can be replicated more easily.
• What are limitations of quasi experiments?

  • Ppts cannot be randomly allocated therefore there may be confounding variables.
  • In both quasi and natural experiments the IV is not deliberately changed by researcher therefore we cannot claim the IV has caused any observed claim.
• What is a random sample?


  A sophisticated form of sampling in which all members of the target populations have an equal chance of being selected.

  The first step in selecting a random sample is to obtain a complete list of all members from target population.

  Secondly all names on the list are assigned a number.

  Finally the actual sample is selected through the use of some lottery method such as random number generator.
• What is a systematic sample?


  When every nth member of the target population is selected. For example every 3rd house on a street.

  A sampling frame is produced which is a list of people in the target population organised into for instance alphabetical order.

  A sampling system is nominated which may begin from a randomly determined start to reduce bias.
• What is a stratified sample?


  Sampling in which the composition if the sample reflects the proportions of people in certain subgroups within the target population.

  The researcher first identifies the different strata from the population.

  Then proportions needed for the sample to be representative are worked out. Finally the ppts that make up each stratum are selected using random sampling.
• What is an opportunity sample?


  Researchers select anyone who is willing and available. The researcher asks anyone who is around at the time of their study.
• What is a volunteer sample?


  Involves ppts selecting themselves to be part of the sample.

  To select a volunteer sample a researcher may place an advert in the newspaper or on a common room noticeboard.
• What is a strength of random sampling?


  A random sample is unbiased. This means that confounding or extraneous variables should be equally divided between the different groups which enhances internal validity.
• What are limitations of random samples?

  • Difficult and time consuming to conduct. A complete list of the target population may be difficult to obtain.
  • May still end up with a sample that is unrepresentative as the random selection may pick people who are all the same for example all in the same social group.
• What is a strength of systematic sampling?


  Sampling method is objective, once the system for selection has been established the researcher has no influence over who is chosen.
• What is a limitation of systematic sampling?


  This method is time consuming and in the end ppts may refuse to take part resulting in a volunteer sample.
• What is a strength of stratified sampling?


  This method produces a representative sample because it is designed to accurately reflect the composition of the population. This means that generalisation of the findings becomes more possible.
• What is a limitation of stratified sampling?


  The identified strata may not reflect all ways in which people are different so therefore may be participant variables.
• What is a strength of opportunity sampling?


  Convenient and less costly in terms of time and money because a list of participants from target population does not need to be identified.