Research Methods

Edexcel A-Level Psychology

Types of Validity

1. Internal Validity → Whether a test/questionnaire assesses what it is intended to assess

2. Predictive Validity → how well the measures can predict future events.

3. Ecological Validity → Extent to which results can be generalised beyond a particular study

Types of Reliability

1. Inter-rater reliability → Checking consistency of data collected from interviews.

2. Test-retest reliability → Checking consistency over time. The same questionnaire/interview is given to the same participants on two occasions to see if the same data is collected.

Types of Experimental Designs

1. Repeated measures design → Each participant takes part in every condition being tested. Demand characteristics and order effects prevented by counter-balancing.

2. Independent groups design → Different participants allocated to two or more experimental groups. Individual differences prevented by random allocation.

3. Matched pairs design → Participants paired on key variables like age and memory. Biased characteristics can be prevented by random allocation.

What are the 2 types of errors?

Type 1: a false positive, occurs in statistical hypothesis testing when the null hypothesis is rejected when it is actually true.

Type II: A false negative, occurs when a statistical test fails to reject a null hypothesis that is actually false. This means that the test concludes there is no effect or difference when, in fact, there is one.

Risk Management

1. Assessment - identify potential physical or psychological harm

2. Management - weigh up short-term and long-term risks

3. Hard to identify all risks at the start of the a study but there must be a way to manage them.

4. Ethics committee decides whether risks are justified

• Procedural risk from what the participants will be asked to do (including 'normalising unhealthy behaviours' and 'creating self-doubt')

• Environmental risk from where the research will take place (including fire hazards)

• Safeguarding risks for vulnerable persons (including vetting researchers to work with children)

• Social risks from what will be done with the data

Mitigating risk involves setting up strategies to plan for risk and reduce it. Risk-mitigation isn't always possible. In deciding whether to go ahead, researchers need to weigh up theseverityof the risk and thelikelihoodof the risk.

Purpose Of Interviews

Interviews are a useful way to find out what people think and feel. Interview data may lack validity because of social desirability bias, so people may present themselves in a ‘good light’ or underplay their problems to fit into prosocial behaviour.

Case Studies

• Could be one person, a group of people or an event

• May take one day, a month or several years

• Method of triangulation

• Mainly qualitative

• Can collect quantitative data

• May be about unusual or unique cases

• Case history - record of a person’s experiences or behaviours

STRENGTHS:

• Investigates rare behaviours or events for the benefit of society

• A complex interaction of many factors can be studied to produce rich, in-depth data

WEAKNESSES:

• Difficult to generalise

• Case history is required

• Researchers may lack objectivity

• Ethical issues - anonymity

Questionnaires VS Interviews

Questionnaires:

• Easy distribution - Large sample size for data analysis

• People may be more willing to reveal confidential information than in an interview

• How the researcher influences a question may impact how the participants respond, reducing internal validity of results.

Interviews:

• Numbers of participants are limited by time and expense

• People may reveal more information as a skilled interviewer can encourage more thoughtful responses

• Both qualitative and quantitative data can be collected.

Levels of Measurement

Nominal Data → Categorical

Ordinal → Ranked Scale

Interval → Data is measured using equal intervals

Scientific Status/Research

1. Replicability

2. Reliability

3. Validity

4. Reductionism

5. Falsification

6. Empiricism - knowledge and claims can only come through experiments and direct research

7. Use of controls

8. Credibility

Evaluation Of Structured Interviews

STRUCTURED INTERVIEW: Pre-determined questions are delivered by an interviewer who does not probe beyond the answers received but may answer questions from the interviewee.

STRENGTHS:

• High reliability

• Easy for analysis

• Interviewer can explain questions - increasing validity of interviewee’s responses

WEAKNESSES:

• Interviewer bias

• Participants may be reluctant to reveal personal information

Evaluation Of Semi-structured & unstructured Interviews

SEMI-STRUCTURED & UNSTRUCTURED INTERVIEWS: Some questions are pre-determined but new questions develop as the interview proceeds.

STRENGTHS:

• More detailed responses

WEAKNESSES:

• Interviewer bias

• Needs well trained interviewers

How to test for reliability?

1. Test-retest method - complete again at a different time to check consistency of results

2. Split-Half Method - split question in half and compare the score in each half

Correlational Research

Measures the relationship between two co-variables

EVALUATION:

STRENGTHS:

1. Cost-effective

WEAKNESSES:

1. Can’t tell cause and effect

2. Unable to tell if there is a third factor

3. The use of secondary data subjects research with the same mistakes as previous research

Content Analysis

• Research tool for analysing content of texts, images for certain words/concepts

• Pre-determined categories

• Count number of times each category appears

• Qualitative analysis can be used to examine the meaning and relationship of words

• Clear and easily understandable categories are necessary for valid conclusions

Evaluation Of Content Analysis

STRENGTHS:

• Ethical - unobtrusive

• Confidential use of sources

• Can document trends over time

• high reliability - replicated using the same categories

WEAKNESSES:

• subjective & biased

• purely descriptive

• potential issues with internal validity

• trends may not accurately affect reality