Representativeness and generalisability in research

Representativeness refers to how well a sample reflects the key characteristics of the target population, ensuring that findings can be applied more broadly. Generalisability is the extent to which results from a specific study or sample can be extended to other groups or contexts.

Reliability and its different forms in psychological studies

Reliability measures the consistency of a test or research method. If a study or tool produces consistent results under similar conditions, it is considered reliable.

Types of reliability in research

• Internal reliability - Assesses consistency within a test itself, ensuring all parts of the measure produce similar results.
• External reliability - Evaluates whether a test yields the same results when repeated in identical conditions or how much results vary over time.
• Inter-rater reliability - Measures the consistency between two or more researchers observing or rating the same behaviour. A positive correlation between their ratings indicates strong inter-rater reliability, often established through pre-tests to standardise interpretation.
• Test-retest reliability - Involves administering the same test to the same group on two separate occasions. High correlation between the two sets of scores suggests good reliability.
• Split-half reliability - Tests internal consistency by dividing a measure into two halves and comparing the results. A strong correlation between the halves indicates the test is reliable.

Validity and its various types in research design

Validity determines how accurately a study or test measures what it intends to measure. High validity ensures that research findings are meaningful and reflect the true nature of the concept under investigation.

Different forms of validity

• Internal validity - Focuses on whether the study's design ensures that changes in the dependent variable are directly caused by the independent variable, minimising the impact of confounding factors.
• Face validity - Assesses whether a measure appears, on the surface, to test what it claims to.
• Construct validity - Examines whether the concept being measured actually exists.
• Concurrent validity - Compares different measures of the same concept to see if they produce similar results when applied simultaneously under the same conditions.
• Criterion validity - Evaluates whether a measure can predict outcomes on another related measure of the same concept.
• Population validity - Considers whether findings from a specific sample can be generalised to the entire target population.
• Ecological validity - Determines if results from a study reflect real-life situations or can be applied to different contexts beyond the research setting.

Influences on participant behaviour and researcher bias

Various factors can affect how participants behave during a study and how researchers interpret data, potentially skewing results.

Factors affecting participant behaviour

• Demand characteristics - Features or cues within an experiment that hint at the study's purpose, leading participants to alter their behaviour to align with perceived expectations.
• Social desirability - The inclination of participants to act or respond in ways they believe are socially acceptable, rather than reflecting their true thoughts or behaviours.

Sources of researcher and observer influence

• Researcher bias - Occurs when a researcher's personal beliefs, cultural background, or gender influence the study's design or interpretation of results.
• Observer bias - Happens when an observer records behaviours based on expectations or preconceptions rather than what is actually observed.
• Researcher effects - Negative impacts on a study caused by the researcher's presence, beliefs, or characteristics.
• Observer effects - Influences on a study due to an observer's presence or characteristics, especially when participants are aware of being observed.

Ethical considerations in psychological research

Ethical guidelines ensure that psychological research is conducted responsibly, protecting participants and maintaining the integrity of the field. These principles are guided by frameworks such as the British Psychological Society's (BPS) Code of Ethics and Conduct.

Key ethical principles and areas

• Respect for participants:
  • Informed consent - Participants must be given enough information about the study to make an informed decision about whether to take part.
  • Right to withdraw - Participants should know they can leave the study at any time and have their data removed.
  • Confidentiality - Personal information and results must be securely stored and not disclosed to anyone outside the research team.
• Competence of researchers:
  • Researchers must operate within their expertise, avoiding giving unqualified advice, and should consult peers to ensure research is conducted appropriately.
  • Monitoring of competence is essential to maintain high standards in research practices.
• Responsibility towards participants:
  • Protection of participants - No greater physical or psychological harm should be caused than what participants might encounter in daily life.
  • Debriefing - After participation, a full explanation of the study's aims and potential impacts should be provided, ensuring participants leave in a state as positive as, or better than, when they arrived.
• Integrity in research:
  • Avoidance of deception - Participants should not be intentionally misled about the purpose or procedures of the study, maintaining honesty and transparency.