Week 3 Workbook: Measurement & Validity

This set of flashcards covers key concepts and principles related to measurement and validity in psychological research, including operational definitions, reliability, validity types, and ethical considerations.

What is operationalisation in psychological research?

The process of converting an abstract construct into an observable, measurable variable by specifying the exact procedures used to measure or manipulate it.

Why is operationalisation essential in psychological research?

Because conclusions depend on whether the operational definition captures the construct intended to study.

Provide an example of operationalising stress.

Stress could be operationalised as (a) a self-report score on a 10-point scale or (b) salivary cortisol concentration in nmol/L.

What are the three criteria for judging operational definitions?

Theoretical alignment, empirical support, and practical feasibility.

How can happiness be operationalised for a campus survey?

As (a) a one-item life satisfaction rating or (b) a salivary oxytocin assay.

What is the main reason the one-item life satisfaction rating is preferred in a campus survey?

Due to its superior practical feasibility and acceptable theoretical alignment.

How does the operational definition determine the variable?

The variable is the numerical outcome defined by the measurement procedure, thus impacting the interpretations made from data.

What two indices are proposed for measuring attention in a pilot study?

Behavioural: mean reaction time and accuracy on a performance task; Physiological: heart-rate variability (RMSSD).

What is the difference between the independent variable (IV) and dependent variable (DV) in an experiment?

The IV is manipulated (e.g., daily meditation), while the DV is the measured outcome (e.g., stress levels).

What does the mnemonic 'Independent is X-tra special, so it gets its own axis' refer to?

It helps students remember that the IV is plotted on the X-axis and the DV on the Y-axis.

Classify the variable 'postcode.'

Nominal; categories with no order; numbers are labels identifying locations.

Why are 'twice as much' statements invalid for interval scales?

Because interval zero is arbitrary, making such ratios meaningless.

What level of measurement is best for a Likert-type scale item?

Strictly ordinal; it has ordered categories with unknown equal gaps.

How can misclassifying the level of measurement affect study results?

It can lead to incorrect conclusions about the data and its relationships.

Differentiate between random and systematic error.

Random error involves unpredictable fluctuations impacting reliability, while systematic error entails consistent bias affecting validity.

What is reactivity in psychological measurements?

Behaviour changes simply because participants know they are being observed.

How can demand characteristics influence study results?

They provide cues that reveal expected behaviours to participants, potentially affecting their responses.

Name two response biases and how reverse-wording helps.

Acquiescence and social desirability; reverse-wording can expose inconsistent endorsement and normalize scoring.

What is test-retest reliability?

It is when the same measure is administered twice to the same participants to correlate scores.

What is a strength of parallel-forms reliability?

It reduces memory or practice effects because two equivalent versions are used.

Why is poor test–retest reliability a concern?

It indicates unstable scores, which limits the validity of conclusions that can be drawn.

What does validity ask in the context of measurement?

Whether evidence and theory support the interpretations made from scores.

What is an example of a feature that protects internal validity?

Random assignment, which balances confounding variables across groups.

Explain the dartboard analogy regarding reliability and validity.

Reliable but invalid is like darts clustered far from the bullseye; valid but unreliable is darts near the bullseye but scattered.

What validity conclusion can be drawn if an anxiety scale correlates with other anxiety scales but does not predict real-world avoidance?

Strong convergent validity but weak predictive validity for behavioural avoidance.

Why must norms be checked in testing?

Norms are reference distributions, so poor matches or outdated norms can distort interpretation and reduce validity.

What are two types of measurement bias in cross-cultural work?

Content bias (items unfamiliar to some groups) and method bias (translation differences).

What is one ethical consideration when deploying a new scale in community settings?

Conducting a risk–benefit analysis.

What conclusions can be made about the reliability and validity of a self-report procrastination scale?

High reliability with questionable validity for predicting behaviour.