Construct Validity & Operationalisation – Research Methods (Psychology 2SOC)
Acknowledgement of Country
- Lecturer begins by paying respect to the traditional custodians of country throughout Australia.
- Recognises their ongoing connection to land, sea and community.
- Extends respect to Elders (past, present) and to all Aboriginal and Torres Strait Islander peoples.
Constructs & Theoretical Building Blocks
- Constructs = abstract, general ideas that underpin theories.
- Examples mentioned: “positive contact”, “liking”, “aggression”.
- Importance:
- They organise observations and predict future findings.
- Cannot be observed directly; require operationalisation.
Construct Validity (CV)
- Definition: The degree to which an operationalisation (measure or manipulation) truly reflects the intended construct.
- Central Questions:
- Does the manipulation create the state we claim?
• E.g., Does doing a jigsaw puzzle with an older person truly represent “positive contact”? - Does the measure capture the construct?
• E.g., Is asking “On a scale of 1–10 how much do you like older people?” sufficient to capture “liking”?
- Significance: Without good CV, findings cannot properly test or refine theory.
Operationalising Variables
- Two broad tasks:
- Manipulation of Independent Variables (IVs).
• Must induce the conceptual state (e.g., create positive vs. no contact). - Measurement of Dependent Variables (DVs).
• Must reflect the conceptual outcome (e.g., behavioural, attitudinal, physiological indices of liking).
- Choices are non-trivial; involve creativity, cost, ethics, and practicality.
- IV manipulation: Completing a jigsaw puzzle with an older person vs. simply being in the same room.
- DV options discussed:
- Self-report liking scale 1–10.
- Behavioural indices: seating distance, willingness to help, time spent.
- CV Issues:
- Is cooperative puzzle-doing the “best” instantiation of positive contact?
- Which DV best generalises to real-world outcomes?
Example 2 – Defining & Measuring Aggression
- Broad definition: Behaviour intended to harm or cause pain.
- Key Distinctions:
- Hostile (angry) aggression: harm is the primary goal.
- Instrumental aggression: harm is a means to another end (e.g., nurse giving an injection to protect public health).
- Implications for CV:
- A theory about temperature increasing aggression may only apply to hostile aggression.
- Measurement choice (e.g., noise-blast paradigm vs. willingness to inflict pain for money) must align with the subtype under investigation.
Ensuring Construct Validity
- Careful, theory-driven decision making.
- Trial-and-error across multiple studies; continuous refinement.
- Use multiple measures or multiple operationalisations within a single study to triangulate the construct.
Measurement Approaches
Self-Report
- Formats: questionnaires, interviews, Likert items, semantic differentials, free response.
- Strengths:
- Efficient, inexpensive, can tap unobservable states (thoughts, plans, attitudes toward AI, etc.).
- Weaknesses:
- Social desirability bias – people present an overly positive self-image.
- Limited self-knowledge or poor recall (e.g., estimating hours volunteered in last 12 months).
- Question-order & wording effects.
- Reviewers routinely scrutinise psychometric quality.
Behavioural Observation
- Data: counts, latencies, durations, choice patterns (e.g., lever presses by rats when light is on).
- Procedures:
- Create situations where target behaviour can occur (e.g., allow volunteering time; record conversations for warmth).
- Use trained raters; assess inter-rater reliability (agreement among observers before combining or averaging ratings).
- Strengths:
- Less reliant on introspection; can capture implicit processes.
- Weaknesses:
- Reactivity (participants alter behaviour when watched).
• Hidden cameras raise major ethical issues; two-way mirrors require disclosure. - Observer biases – mitigated via multiple raters and reliability statistics.
Physiological & Technological Measures
- Reaction-time paradigms: how quickly a key is pressed after a stimulus.
- Eye-tracking: gaze location reveals attention patterns.
- Experience Sampling (ESM):
- Smartphones “ping” participants multiple times per day with brief surveys (e.g., 3 items on happiness, busyness).
- Can embed manipulations (e.g., instruct one group to perform 10 helpful acts in a week).
- Classic & emerging biosignals: heart rate, galvanic skin response, neuro-imaging (EEG, fMRI).
• Portability & cost remain challenges (e.g., portable fMRI not yet feasible). - Trade-offs:
- Higher ecological validity in ESM; higher cost/complexity in neuro-tech.
Reliability & Agreement
- For observational data:
- Multiple raters quantify the same behaviour (e.g., warmth on 1–7 scale).
- Combine scores only when inter-rater consistency is acceptable.
- For self-report scales: internal consistency, test–retest reliability, factor structure all scrutinised to support validity claims.
Ethical & Practical Constraints
- Informed consent limits covert recording.
- Hidden cameras/two-way mirrors rarely approved by ethics committees.
- Technology (beepers, phones) must respect privacy and minimise participant burden.
Iterative Nature of Social-Psychological Research
- Progress via competing theories and competing operationalisations.
- Single studies rarely decisive; body of evidence (multiple methods, replications) builds confidence.
- Construct validity is re-evaluated each time a new measure/manipulation is introduced or an unexpected result emerges.
Key Take-Home Messages
- Good research requires a tight link between abstract constructs and concrete operations.
- No single operationalisation is perfect; convergence across methods strengthens conclusions.
- Awareness of strengths, weaknesses, ethical issues, and cost guides methodological choices.
- Construct validity sits at the heart of theory testing, demanding critical scrutiny at every stage of the scientific process.