Consider the three types of investigation in psychological research written in alphabetical order:
(a) Controlled laboratory experiments;
(b) Ex post facto studies; and
(c) Field experiments.
Arrange them in descending order in terms of their ability to control secondary variance usually.

Correct option is A

The ability to control secondary variance (extraneous variables) decreases from Controlled laboratory experiments (highest control through manipulation and isolation), to Field experiments (moderate control with real-world settings but experimental manipulation), to Ex post facto studies (lowest control as independent variables have already occurred and cannot be manipulated). Laboratory experiments maximize internal validity through strict control of confounding variables. Field experiments maintain experimental control but sacrifice some precision for ecological validity. Ex post facto designs are retrospective and correlational, offering minimal control over extraneous factors, relying on statistical rather than experimental control.

Information Booster:
● Controlled Laboratory Experiments: Highest control over extraneous variables; use random assignment, standardized procedures, and controlled settings to isolate the independent variable's effect
● Secondary Variance: Also called error variance or systematic bias; includes confounding variables that threaten internal validity
● Field Experiments: Conducted in natural settings with experimental manipulation; balance between control and ecological validity; examples include educational interventions in schools
● Ex Post Facto Research: "After the fact" studies where the IV has already occurred; researcher examines existing group differences (e.g., smokers vs. non-smokers); cannot establish causation
● Control Hierarchy: Laboratory > Field > Ex post facto in terms of causal inference capacity
● Campbell and Stanley's Validity Framework: Laboratory experiments minimize threats to internal validity; field experiments balance internal and external validity; ex post facto designs are vulnerable to multiple validity threats