Pilot Studies + Ethical Issues + Sampling

• Internal validity is about what goes on inside an experiment and it refers to how controlled the study is.
• What are the different types of external validity?

  Ecological , population , temporal
• External validity is about generalising the findings from a study to other situations
• The Types of External Validity

  ecological - application of findings within the study to the real world. population - application of findings within the study to other types of people. temporal - application of findings within the study to different periods of time
• What is mundane realism?

  The ability to set/complete tasks that are more like what youd do in everyday life
• Low mundane realism decreases internal validity.
• Key word- Generalisability: The extent to which findings can be generalised / extended to natural settings
• A sample is the participants that form part of the research. There is a general population , a target population and the sample. The population refers to the large group of individuals. For economic and practical reasons, it isn't possible to include all members of the target population, so the researcher selects a smaller group- a sample.
• Samples that are drawn will be representative of the target group so that generalisation is possible. Most samples contain some degree of bias.
• What are the 4 sampling techniques?

  We remember them using the acronym VROSS.

  • Volunteer sample
  • Random sample
  • Opportunity sample
  • Systematic sample
  • Stratified sample.
• How might each sample be done?

  Volunteer - advertisements / willing pps could raise their hand when asked

  Random - list all members within target population and select through the use of the lottery method (random generator)

  Opportunity - researcher would just ask whoever is around at the time of the study (eg: on the street)

  Systematic - putting the target population into a sampling frame. (eg: alphabetical order). they'd begin randomly to reduce bias.

  Stratified - researcher identifies different strata that makes up the population (pps in each stratum are selected through random sampling).
• Evaluation of Sampling Techniques (Volunteer)

  • STRENGTHS: less time consuming and the researcher ends up with people who are more engaged.
  • WEAKNESSES: there would be bias and asking volunteers may attract a certain profile of people.
• What is a pilot study?

  A small scale version of an investigation that takes place before the real investigation is conducted.

  • It is conducted to save time and money being wasted on research that could be useless.
  • The aim of piloting is to allow the researcher to make changes/modifications if necessary.
  • The data collected from a pilot study is not included in the final data set
• Ethical Issues

  Informed consent is an ethical issue. participants should know what they're getting themselves into. however, this means the participants behaviour wont be natural. Ways to deal it:

  • Presumptive consent - asking a similar group of people if the study is acceptable.
  • Prior general consent - pps give their permission to take part in a number of different studies, including the one that involves deception. by consenting, pps consent to being deceived.
  • Retrospective consent - pps are asked for their consent, during a debrief, after having already been a part of the study
• Ethical Issues

  Deception is an ethical issue, but may be needed to get participants to behave naturally. To deal with deception, at the end of a study, the participants should be given a full debrief with should include the true aims to the study, what the data will be used for and any other details.
• Ethical Issues

  Privacy and confidentiality. participant should have the right to control information about themselves. To deal with privacy and confidentiality:

  • If personal details are held, they must be protected by allowing participants to remain anonymous.

  This can be done by using pseudonyms, initials or if needed- blurring faces.
• Ethical Issues

  Protection from harm. Participants should be protected from physical and psychological harm and must be reminded about their right to withdraw at any time.
• • Ethical issues arise when a conflict exits between the participants rights and the researchers' need to gain data / valuable information
  • The role of ethics committees is to make judgments about the cost and benefits involved in carrying our a research. the benefits should outweigh the costs.
  • The British Psychological Society came up with the code of ethics in 2009
• Evaluation of Sampling Techniques (Random)

  STRENGTHS: sample is potentially unbiased, meaning that extraneous variables would be equally divided between the different groups. this increases internal validity.

  WEAKNESSES: may be time consuming. a complete list of the target population may be difficult to get. the randomly picked names could potentially be an unrepresentative sample.
• Evaluation of Sampling Techniques (Opportunity)

  STRENGTHS: its convenient and less costly

  WEAKNESSES: may be unrepresentative of the target population. there could be researcher bias, so findings cant be generalised.
• Evaluation of Sampling Techniques (Systematic)

  STRENGTHS: sampling is objective as the researcher has no influence over who is chosen.

  WEAKNESSES: may be time consuming as a complete list of the target population may be difficult to get. and may end up with an unrepresentative sample.
• Evaluation of Sampling Techniques (Stratified)

  STRENGTHS: produces a representative sample because its designed to reflect the composition of the population. Generalisation of findings is possible.

  WEAKNESSES: the strata doesn't reflect all the ways that people are different, so complete representation of the target population isn't possible.