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Causal Limitations of Quasi-Experimental Research
While quasi-experimental research manipulates an independent variable before measuring a dependent variable, it still cannot definitively establish cause-and-effect relationships. The absence of random assignment or counterbalancing means researchers cannot confidently rule out confounding variables—pre-existing differences between conditions—as the true cause of any observed outcomes.
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Ch.2 Psychological Research - Psychology @ OpenStax
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Introduction to Psychology @ OpenStax Course
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OpenStax Psychology (2nd ed.) Textbook
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Research Methods in Psychology - 4th American Edition @ KPU
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Example of a Quasi-Experimental Study: Sex and Spatial Memory
One-Group Posttest Only Design
One-Group Pretest-Posttest Design
Nonequivalent Groups Design
Example of a Quasi-Experimental Study: Anti-Bullying Program
Selection Effect
Comparison of Internal Validity Across Research Designs
Tuskegee Syphilis Study
Elimination of Directionality Problem in Quasi-Experiments
Applications of Quasi-Experimental Research
Causal Limitations of Quasi-Experimental Research
Which of the following is a key characteristic that distinguishes quasi-experimental research from a true experiment?
Match each feature of a quasi-experimental design with the specific role it plays or the consequence it has on the quality of a psychological research study.
A clinical psychologist evaluates the effectiveness of a new mindfulness-based therapy by providing the treatment to all patients at one clinic while patients at a neighboring clinic receive standard care. Because the researcher is manipulating the treatment but is using pre-existing groups rather than assigning individual patients to conditions by chance, this study is best categorized as a(n) _________ research design.
A psychologist is testing the impact of a new peer-mentoring program in a local high school. Arrange the logical sequence of steps the psychologist would take to conduct a study that follows a quasi-experimental design and evaluates the strength of its causal claims.
A researcher claims that their quasi-experimental study provides the same level of confidence in causal conclusions as a true experiment because both designs involve the manipulation of an independent variable. This evaluative claim is scientifically sound.
Although quasi-experimental research offers more control than purely correlational studies, it generally possesses lower internal validity than a true experiment because it lacks random assignment or counterbalancing.
A researcher evaluates a new educational software by implementing it in one classroom and comparing the results to another classroom that continues with the standard curriculum. Which statement best explains why this quasi-experimental design has lower internal validity than a true experiment, yet still provides more control than a purely correlational study?
A psychology instructor asks students to match scenarios with their corresponding design feature. Match each research description to the quasi-experimental design feature or consequence it applies.
An investigator is analyzing the methodological differences between two research proposals. Study A uses random assignment and counterbalancing, whereas Study B implements a comparison condition using pre-existing groups without random assignment. In analyzing their quality, the investigator concludes that Study B generally possesses lower _____ than Study A.
Evaluate the following research design scenarios based on the standard of internal validity and control established in methodology. Arrange them in order from the design that provides the HIGHEST level of internal validity to the design that provides the LOWEST level of internal validity.
Define quasi-experimental research and identify the specific methodological features of a true experiment that it frequently lacks, as well as its position relative to purely correlational and true experimental research regarding internal validity.
Based on the provided scenario, diagnose the type of research methodological design being used and justify why this design possesses lower internal validity compared to a true experiment.
A researcher conducts a study on memory where all participants complete the exact same sequence of tasks, introducing potential order effects. What specific methodological control should the researcher apply to this design to address these order effects and move it closer to a true experiment?
Two approaches to removing confounds
Example of Spurious Correlation: Ice Cream Sales and Crime Rates
Analyzing a Research Finding
Interpreting Correlational Research
Between-Subjects Experiment
Example of a Confounding Variable: Mood and Memory
Causal Limitations of Quasi-Experimental Research
What type of variable is an extraneous factor that differs on average across levels of the independent variable, providing a plausible alternative explanation for any observed difference?
A researcher conducts a study to see if drinking caffeinated coffee improves memory performance. Participants in the 'Caffeine' group drink coffee in a warm, quiet cafe, while those in the 'Decaf' group drink coffee in a noisy, cold laboratory. Match each element of this study to its corresponding variable role.
A researcher investigates whether a new herbal supplement improves sleep quality. She gives the supplement to a group of participants who also practice daily meditation, while the control group receives a placebo and does not meditate. In this study, the practice of meditation is a confounding variable.
Arrange the logical steps a researcher takes to analyze how an extra factor becomes a confounding variable that invalidates the causal conclusions of an experiment.
A researcher concludes that a new 'morning exercise' routine improves worker productivity; however, the group assigned to the exercise routine was tested at 9:00 AM, while the control group was tested at 3:00 PM. When evaluating the validity of the researcher's causal conclusion, the 'time of day' must be recognized as a ________ variable because it varies systematically with the independent variable and offers a plausible alternative explanation for the results.
Any extraneous variable present in an experiment is automatically classified as a confounding variable.
Which statement best explains the difference between a 'simple' extraneous variable and a 'confounding' variable in an experiment?
Match each research scenario to the extraneous variable that functions as a confounding variable in that study.
A researcher studying the effect of sleep deprivation on reaction time notices that participants in the sleep-deprived condition consumed, on average, far more caffeine than participants in the well-rested condition. To classify caffeine as a confounding variable rather than a mere extraneous variable, the researcher must confirm that caffeine consumption _____ across the two experimental conditions.
A peer reviewer is evaluating whether a study's causal conclusion is compromised by a confounding variable. Arrange the following evaluative steps in the order a careful reviewer should apply them.
Based on the definition of a confounding variable in psychological research, define what a confounding variable is. In your answer, explain how it behaves in relation to the independent variable and describe the primary scientific challenge it introduces when researchers attempt to establish a cause-and-effect relationship.
In the context of this study, identify the independent variable, the dependent variable, and the confounding variable. Explain how the confounding variable behaves systematically in relation to the independent variable, and explain why this prevents the researcher from drawing a clear cause-and-effect conclusion about the app's effectiveness.
A cognitive psychologist runs an experiment to test the effect of background noise (classical music vs. silence) on memory recall. Participants in the music condition are tested in a warm, comfortable room with soft lighting, whereas participants in the silent condition are tested in a cold, uncomfortable room with harsh fluorescent lighting. Apply the concept of a confounding variable to this scenario to identify the confounder, explain how it systematically co-varies with the independent variable, and describe the threat it poses to the study's validity.
Example of a Confounding Variable: Temperature
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A researcher observes that children who attend a private preschool have higher reading scores in first grade than children who attend a public preschool. The researcher concludes that attending private preschool causes an increase in reading ability. Which statement provides the most accurate critique of this conclusion?
What is the primary reason that quasi-experimental research cannot definitively establish cause-and-effect relationships?
Because researchers manipulate an independent variable before measuring the outcome, quasi-experimental designs can confidently rule out confounding variables and establish definitive cause-and-effect relationships.
Match each research scenario with the specific confounding variable that prevents a definitive causal conclusion due to the lack of random assignment.
Arrange the following steps in the logical order a researcher would use to analyze why a quasi-experimental study comparing non-equivalent groups fails to establish a definitive cause-and-effect relationship.
Match each term related to the causal limitations of quasi-experimental research with its corresponding description.
In quasi-experimental research, why is the manipulation of an independent variable insufficient for establishing a definitive cause-and-effect relationship?
A researcher concludes that a new wellness program 'caused' a decrease in employee stress after comparing two different branch offices. An evaluator critiques this conclusion as invalid for establishing definitive causality. This judgment is based on the fact that the study lacks _____, which prevents the researcher from ensuring the groups were equivalent before the program began.
A researcher compares anxiety levels between two intact college dormitories: one dormitory received a new mindfulness workshop (the manipulation) before anxiety was measured, while the other dormitory did not. Because the independent variable was introduced before measuring the dependent variable, this quasi-experimental design provides definitive evidence that the workshop caused the reduction in anxiety levels.
A methodologist reviewing a quasi-experimental study notes that two intact schools were compared—one adopted a new reading curriculum and one did not. Even though the curriculum (the independent variable) was introduced before post-test scores (the dependent variable) were collected, the methodologist concludes the study cannot establish a definitive cause-and-effect relationship because _____ between the two schools cannot be eliminated as a rival explanation for score differences.
A peer reviewer is judging whether a quasi-experimental study's causal conclusion is justified. Arrange the following evaluative steps in the order that best builds toward a defensible final verdict on the study's causal claim.
According to the course content on the causal limitations of quasi-experimental research, what two specific design features are absent in this type of research, and what is the consequence of their absence on a researcher's ability to draw causal conclusions?
Based on the concept of causal limitations in quasi-experimental research, explain why the colleague is correct. What specific methodological issue prevents a definitive cause-and-effect conclusion here?
A clinical psychologist evaluates a new therapy by comparing an existing therapy group at Clinic X to an existing control group at Clinic Y. If the psychologist finds a significant reduction in symptoms at Clinic X, how should they write a brief statement for their research paper's discussion section that accurately reflects the causal limitations of this design?