Psychometrics & Questionaire Design

Individual Differences Lecture 2

Psychometrics

The field of study concerned with the theory and technique of psychological measurement, which involves the measurement of knowledge, abilities, attitudes, and personality traits.

Ideographic Approach

An approach focusing on the individual, emphasizing unique characteristics through qualitative methods such as case studies and interviews.

Nomothetic Approach

An approach that focuses on identifying general laws and similarities among individuals, often using quantitative methods and psychometric tests.

Qualitative Methodologies

Research methods that obtain non-numerical data, often through interviews, case studies, and narratives to understand individual experiences.

Quantitative Methods

Research methods that focus on quantifying data and often involve statistical analysis to explore relationships between variables.

Validity

The extent to which a test measures what it claims to measure, including various types such as convergent, concurrent, and predictive validity.

Reliability

The consistency of a measure; includes internal reliability (consistency of items within a test) and test-retest reliability (stability of test results over time).

Good Questionnaire Design

A well-designed questionnaire should have clarity, unambiguous wording, and avoid leading or embarrassing questions.

Response Format

The way in which respondents are asked to provide their answers, which can include binary choices (yes/no) and Likert-type scales.

Ethical Considerations

Important factors in research that ensure participants are informed about the study, their data is protected, and that deception is ethically justified.

Psychometrics

The field of study concerned with the theory and technique of psychological measurement, which involves the measurement of knowledge, abilities, attitudes, and personality traits.

Ideographic Approach

An approach focusing on the individual, emphasizing unique characteristics through qualitative methods such as case studies and interviews.

Nomothetic Approach

An approach that focuses on identifying general laws and similarities among individuals, often using quantitative methods and psychometric tests.

Qualitative Methodologies

Research methods that obtain non-numerical data, often through interviews, case studies, and narratives to understand individual experiences.

Quantitative Methods

Research methods that focus on quantifying data and often involve statistical analysis to explore relationships between variables.

Response Format

The way in which respondents are asked to provide their answers, which can include binary choices (yes/no) and Likert-type scales.

What's the difference between idiographic and nomothetic approaches?

The idiographic approach focuses on unique individual characteristics using qualitative methods, while the nomothetic approach identifies general laws across individuals using quantitative methods.

Why do we compare idiographic and nomothetic approaches?

Comparing them highlights different aims in psychological research: understanding individual depth (idiographic) vs. establishing general principles (nomothetic) to provide a comprehensive view of personality.

What are psychometric tests used for?

Psychometric tests are used for the measurement of knowledge, abilities, attitudes, and personality traits, as part of the field of psychometrics.

What makes a good questionnaire item?

A good questionnaire item should have clarity, unambiguous wording, and avoid leading or embarrassing questions.

Give an example of a bad question.

An example of a bad question is a leading question like, 'Don't you agree that the new policy is excellent?' or an ambiguous one like, 'Do you go out often?' without defining 'often'.

What are common types of response scales?

Common types of response scales include binary choices (e.g., yes/no) and Likert-type scales (e.g., strongly agree to strongly disagree).

What makes a sample representative?

A sample is representative when it accurately reflects the characteristics of the larger population from which it was drawn, allowing findings to be generalizable.

What’s the difference between random and opportunity sampling?

Random sampling ensures every member of the population has an equal chance of being selected, increasing representativeness. Opportunity sampling selects participants who are readily available, which may lead to unrepresentative samples and bias.

Why is sample size important?

Sample size is important because a larger, appropriate sample size typically leads to more reliable and statistically powerful results, reducing the impact of random error and increasing the generalizability of findings.

What are key ethical issues in psychometric research?

Key ethical issues include ensuring participants are informed about the study (informed consent), protecting their data (confidentiality and anonymity), and ensuring that any deception used is ethically justified and followed by debriefing.

What is internal reliability?

Internal reliability refers to the consistency of items within a test, indicating whether different parts of the test measure the same construct.

What is test–retest reliability?

Test-retest reliability refers to the stability of test results over time, indicating how consistent a measure is when administered on different occasions to the same individuals.

What is convergent validity?

Convergent validity is the extent to which a measure correlates with other similar measures (e.g., self-esteem with self-worth).

What is concurrent validity?

Concurrent validity is the correlation of a measure with other measures of the same construct taken at the same time.

What is discriminant validity?

Discriminant validity is the lack of correlation of a measure with unrelated measures (e.g., self-esteem ≠ intelligence).

What is face validity?

Face validity is whether a test looks like it measures the construct at first glance.

What is content validity?

Content validity is whether all aspects of the construct are covered (e.g., all areas of self-esteem).

What is predictive validity?

Predictive validity is whether the test predicts future behaviour (e.g., high self-esteem → more confidence).