Quantitative Research

True Experiment

Method that manipulates an IV to determine effect on DV

Characteristics of a True Experiment

• Random allocation of participants

• Control groups

• Manipulation of the IV

• Control of extraneous variables (controlled/lab environment)

• Establishment of cause-and-effect relationship between variables

Strengths of a True Experiment

• High internal validity due to controlled conditions

• Establishment of causal relationship

• Random allocation reduces bias

• Replicable

Limitations of a True Experiment

• Low ecological validity because of lab settings

• Mundane realism (unrealistic)

Natural Experiment

Researchers observe naturally occurring events or conditions without manipulation of the IV.

Characteristics of Natural Experiments

• IV is a naturally-occurring phenomenon

• No researcher manipulation

• Treatment/control groups form naturally

Strengths of Natural Experiments

• High ecological validity

• Generalizable to the population based on the sample/IV

Limitations of Natural Experiments

• Low reliability / difficult to replicate

• Low validity (confounding variables may impact results)

Quasi Experiment

Participants are not randomly allocated into groups, but assigned based on pre-existing criteria/characteristics

Characteristics of Quasi Experiments

• Non-random allocation

• Picking/assigning participants based on pre-existing criteria/characteristics

Strengths of Quasi Experiments

• High internal validity

• Good ecological validity (replicates real-world settings)

Limitations of Quasi Experiments

• Potential for selection bias

• Less control of confounding variables

• Potential for researcher bias

Correlational Studies

Studies that examine relationships between two or more variables without manipulating them directly.

Characteristics of correlational studies

• No manipulation of variables

• Measures association, not causation

Strengths of Correlational Studies

• More generalizable and easier to conduct

• Reliable (easy to replicate)

• More ethical

Limitations of Correlational Studies

• Low external validity (measures association, not causation)

• Confounding variables not controlled

• Bidirectional ambiguity