Chapter 11: Confounding and Obscuring Variables Threats to Internal Validity

These flashcards cover key concepts, definitions, and prevention techniques related to confounding and obscuring variables that threaten internal validity.

What are Design Confounds?

Occurs when a second variable unintentionally varies along with the independent variable (IV).

How can you prevent Design Confounds?

Use random assignment, include a control group, and employ counterbalancing.

What are Selection Effects?

In an independent-group design, this occurs when the two IV groups have systematically different kinds of participants.

How can you prevent Selection Effects?

Use random assignment and pretests, and ensure a large sample size.

What are Order Effects?

In a repeated measure design, this occurs when the effect of the IV is confounded with carryover from one level to another.

How can you prevent Order Effects?

Use counterbalancing, introduce time breaks, or employ a between-subject design.

What is the Maturation Threat?

An experimental group improves over time due to natural development or spontaneous improvement.

How can you prevent the Maturation Threat?

Use a control group, keep the study duration short, or use random assignment.

What is the History Threat?

An experimental group changes over time due to an external factor affecting most members.

How can you prevent the History Threat?

Include a control group and use random assignment.

What is the Regression Threat?

This occurs when an experimental group's extreme average at pretest changes over time due to random events.

How can you prevent the Regression Threat?

Avoid selecting based on extreme scores and use random assignment.

What is the Attrition Threat?

An experimental group changes over time because the most extreme cases systematically drop out.

How can you prevent the Attrition Threat?

Keep participants engaged, reduce participant burden, and monitor dropouts closely.

What is the Testing Threat?

Changes in an experimental group over time may result from repeated testing affecting participants.

How can you prevent the Testing Threat?

Use a control group that also takes the pretest and employ posttest-only designs.

What is the Instrumentation Threat?

Changes in an experimental group occur due to changes in the measurement instruments.

How can you prevent the Instrumentation Threat?

Use the same instruments throughout the study and train observers thoroughly.

What is Observer Bias?

This occurs when a researcher's expectations influence their ratings of a group.

How can you prevent Observer Bias?

Use blind observers, train observers thoroughly, and use multiple observers.

What are Demand Characteristics?

Participants may guess the study's purpose and alter their behavior accordingly.

How can you prevent Demand Characteristics?

Use deception ethically and implement a between-subjects design.

What is the Placebo Effect?

Participants improve simply because they believe in the efficacy of the treatment they received.

How can you prevent the Placebo Effect?

Include a placebo control group and use a double-blind design.