W2 Research Methods – research designs

Vocabulary flashcards covering key terms from Week Two lecture notes on research design, sampling biases, operationalisation, and variable terminology.

Cross-sectional Design

A research design that captures data from participants at a single point in time.

Longitudinal Design

A research design that captures data from the same participants at two or more points in time.

Experimental Design

A design in which a variable (condition) is actively manipulated and participants are randomly assigned to conditions.

Quasi-experimental Design

A design where variables are not manipulated; participants are placed into naturally occurring ‘conditions’ based on non-random criteria.

Observational Design

A non-manipulative design that measures variables as they naturally occur without intervention.

Within-subjects (Repeated Measures) Design

A design in which every participant experiences all conditions, and their own prior results serve as the comparison.

Between-subjects Design

A design in which each participant experiences only one condition and results are compared across different groups.

Mixed Design

A study that combines both between-subjects and within-subjects assessments.

Population-based Sample

A sample chosen to be representative of the wider population.

Convenience Sample

A non-representative sample selected based on ease of access to participants.

Stratification (Sampling)

Dividing a population into distinct, homogeneous subgroups (strata) based on shared/pre-defined characteristics.

Sample Bias

Systematic error introduced when a sample is not representative of the population of interest.

Self-selection Bias

Bias arising when individuals decide for themselves whether to participate, potentially differing from non-participants.

Healthy Bias

Tendency for people to join studies that align with their preferred or current healthy lifestyles.

Under-coverage Bias

Bias resulting when some members of the intended population are inadequately represented in the sample due to recruitment methods.

WEIRD Sampling Issue

Over-representation of Western, Educated, Industrialised, Rich, Democratic populations (≈80% of participants, 12% of world).

Operationalise

To define exactly how a theoretical construct will be measured or observed, linking abstract ideas to specific, replicable metrics.

Research Aim

A broad statement of what a study intends to achieve.

Research Question

A specific query the study seeks to answer.

Hypothesis

A precise, directional (positive or negative) statement predicting relationships between key constructs

Independent Variable (IV)

In experimental or quasi-experimental research, the variable that is manipulated or naturally varies to explain changes in the dependent variable.

Dependent Variable (DV)

The outcome that is measured to assess the effect of the independent variable.

Predictor Variable

In observational research, the variable believed to influence or predict the outcome variable (analogous to the IV).

Outcome Variable

In observational research, the variable that is measured as the result or effect (analogous to the DV).

Theoretical Construct

An abstract concept that cannot be directly observed (e.g., stress, attitude) and is the target of measurement.

Measure

The method or tool (survey, behavioural observation, brain scan, etc.) used to observe or quantify a theoretical construct.