Interrupted Time-Series Design

Control Group in Pretest-Posttest Designs

History as a Threat to Internal Validity

Maturation as a Threat to Internal Validity

Testing as a Threat to Internal Validity

Instrumentation as a Threat to Internal Validity

Regression to the Mean as a Threat to Internal Validity

Spontaneous Remission

Example of a One-Group Pretest-Posttest Design

Why is it difficult to conclude with certainty that a treatment was effective when using a one-group pretest-posttest design?

A researcher is using a one-group pretest-posttest design to study the effect of a new stress-reduction workshop on college students. Match each component of the study to its specific role in this research design.

A health psychologist wants to evaluate the impact of a weekend nature retreat on stress levels using a one-group pretest-posttest design. Arrange the steps of this study in the correct chronological order.

A researcher evaluates a new study-skills workshop using a one-group pretest-posttest design and observes a significant increase in students' grade point averages at the end of the semester. The researcher can definitively conclude that the workshop caused the increase because the pretest measurement successfully accounts for each participant's individual academic history.

Which of the following describes the basic procedure used in a one-group pretest-posttest design?

A researcher evaluates a new social-anxiety intervention using a one-group pretest-posttest design and finds that participants' anxiety levels are lower at the posttest than they were at the start. When appraising the scientific merit of the claim that 'the intervention caused the change,' a peer reviewer would note that the lack of a comparison group makes it impossible to rule out threats like maturation or history. Consequently, in terms of research design standards, this study is evaluated as having critically low _____ validity.

When using a one-group pretest-posttest design to evaluate a new mindfulness intervention, the researcher uses the pretest to establish a(n) _____ for participants' stress levels before the intervention occurs.

A researcher evaluates a new math tutoring software using a one-group pretest-posttest design. To control for potential order effects, the researcher can counterbalance the study by having half of the participants take the posttest exam before they use the tutoring software.

Analyze the structural differences between a within-subjects experiment and a one-group pretest-posttest design. Match each design characteristic to the research design or feature it describes.

An educational psychologist wants to evaluate the effectiveness of a new reading intervention using a one-group pretest-posttest design. Arrange the steps of the research process and the subsequent evaluation of its findings in the correct chronological and logical order.

Control Group in Pretest-Posttest Designs

In the context of research design, which of the following best defines 'history' as a threat to internal validity?

A history threat to internal validity refers to the possibility that participants' personal backgrounds and past experiences before entering a study caused the observed changes in the dependent variable.

A researcher is conducting a study to see if a new campus security escort service improves students' feelings of safety. Match each element of the research design with the specific event from the scenario that illustrates how a history threat could occur.

A researcher is evaluating a new campus safety program using a pretest-posttest design. Arrange the following events and analytical steps in the correct order to demonstrate how a history threat is identified and evaluated in this research scenario.

Imagine you are designing a research protocol to evaluate the impact of a new 'Social Connectivity' program on elderly residents in a specific city. During your planning, you realize that the city is likely to implement a new 'Free Senior Transit' policy halfway through your $6$-month study—an external event that could independently influence residents' social scores. To construct a research design that effectively isolates the program's unique impact from the influence of this external transit policy, which of the following strategies should you formulate?

A researcher is critiquing a study that reported a $20\%$ increase in gym attendance following the introduction of a new campus fitness program. However, they discover that a highly popular 'New Year's Resolution' social media challenge began nationwide at the exact same time the program started. By judging that this external social trend, rather than the fitness program itself, is the most plausible explanation for the change in behavior, the researcher has identified a(n) _____ threat to internal validity.

In research methodology, an extraneous external event that occurs between the pretest and posttest measurements and provides an alternative explanation for the results is known as a(n) _____ threat to internal validity.

A researcher evaluates a new anti-drug education program using a one-group pretest-posttest design. Between the pretest and posttest measurements, a highly publicized celebrity drug overdose occurs. If the researcher observes a positive change in the participants' attitudes toward avoiding drugs at the posttest, they can confidently conclude that the anti-drug program was the sole cause of this change.

In a study designed to evaluate an anti-drug education program, several events and concepts interact. Match each component of this research scenario with its methodological description.

To evaluate whether history poses a threat to the internal validity of a one-group pretest-posttest study, order the chronological events and evaluation steps from first to last.

Control Group in Pretest-Posttest Designs

Strengths of Switching Replication

Which of the following best describes maturation as a threat to internal validity?

If an observed difference in a study's dependent variable is actually due to participants naturally growing older, learning, or becoming fatigued between measurements, this represents a maturation threat.

A researcher is concerned that maturation is threatening the internal validity of their study. Match each research scenario with the specific type of natural, internal change that is likely influencing the results.

A researcher evaluates a year-long logic intervention for children and finds that their reasoning scores improved significantly. Arrange the steps the researcher should follow to analyze whether this finding is actually due to the intervention or represents a maturation threat.

You are designing a research project to evaluate whether a new 12-month 'Early Literacy' program increases the reading readiness of toddlers. Given that toddlers' reading readiness naturally improves as they mature cognitively over a year, which of the following research plans should you construct to ensure that any observed improvement is due to the program rather than natural maturation?

A researcher concludes that a full-day intensive workshop decreased participants' focus because their test scores were lower at 5:00 PM than they were at 9:00 AM. A colleague argues that participants likely just became naturally tired over the course of the day—not because of the workshop. This alternative explanation is an example of the internal validity threat known as _____.

In psychological research, the threat to internal validity that occurs when participants undergo natural developmental or physiological changes—such as growing older, learning, or becoming fatigued—between pretest and posttest measurements is known as _____.

A researcher evaluates a 10-hour intensive study session by testing students' focus at 9:00 AM (pretest) and again at 7:00 PM (posttest). If the researcher concludes that the study session itself caused a decrease in focus, but the decline was actually due to the students naturally becoming tired, the internal validity of the study is threatened by maturation.

A researcher is analyzing different potential explanations for changes observed between pretest and posttest in a study. Match each description of a participant's change with the specific maturation-related threat it represents.

Arrange the steps a researcher should take to evaluate and control for a potential maturation threat in a pretest-posttest design.

Control Group in Pretest-Posttest Designs

Which of the following best describes the testing threat to internal validity?

A researcher measures a group of college students' awareness of healthy eating by having them complete a detailed nutrition-knowledge questionnaire. Two weeks later—without any intervention—the researcher administers the same questionnaire and finds that scores have improved. The researcher suspects that completing the first questionnaire prompted students to read about nutrition and discuss dietary habits with friends, which led to the higher scores on the second administration. This scenario illustrates a threat to the study's internal validity caused by the act of initial measurement itself influencing later performance.

A cognitive psychologist wants to determine if listening to a 'Focus Music' playlist improves concentration. Arrange the following events in the order they would occur to illustrate a testing threat in this research study.

Analyze the following research outcomes in a one-group pretest-posttest study and match each specific observation to the mechanism of the testing threat it illustrates.

A researcher reports that posttest scores on a spatial-reasoning task were $15\%$ higher than pretest scores in a single-group study. While the researcher claims the intervention worked, a critic evaluates the study's internal validity as low, arguing that the improvement was simply due to participants becoming accustomed to the task's instructions and timing during the first measurement. The critic's judgment identifies a ________ threat.

Researchers are conducting a study on a new cognitive training program. They administer a baseline memory test (pretest) on Monday, provide the training on Wednesday, and administer the same memory test (posttest) on Friday. Which of the following concerns specifically describes a testing threat in this context?

The _____ threat to internal validity occurs when the mere act of taking a pretest inadvertently influences a participant's responses on the subsequent posttest.

Control Group in Pretest-Posttest Designs

Strengths of Switching Replication

Which of the following best describes how instrumentation threatens a study's internal validity?

An instrumentation threat can occur even if the measurement process becomes more accurate over time, such as when a researcher gains skill in coding behaviors between the pretest and the posttest.

A clinical psychologist is conducting a six-month study on the effects of a new therapy. Match each scenario occurring between the pretest and posttest to the specific way it functions as an instrumentation threat to internal validity.

A developmental psychologist is studying the impact of a 'kindness curriculum' on playground behavior. Analyze how an instrumentation threat leads to a false conclusion by ordering the events of the study from the initial measurement to the final logical error.

An instrumentation threat to internal validity can occur if participants change their approach to a measurement tool, such as becoming bored or less careful with their responses, between the pretest and the posttest.

A developmental psychologist measures 'cooperative play' in toddlers using a specific behavioral checklist. If the psychologist becomes significantly more skilled at spotting these behaviors by the time of the posttest, the resulting data suffers from an instrumentation threat because:

A senior researcher is evaluating a peer's study on classroom aggression. They notice that the observers were extremely strict during the pretest but became fatigued and more lenient by the posttest, leading to a recorded 'decrease' in aggression that likely does not exist. The researcher rejects the study's conclusions, judging that the measurement standards shifted over time. To justify this critique of the study's internal validity, the researcher would cite a(n) _____ threat.

A clinical psychologist is evaluating a new mindfulness program and administers a psychological survey before and after the intervention. Match each scenario describing a change in the measurement process to the type of instrumentation threat it represents.

An educational psychologist measures classroom engagement. In the pretest, the observers are fresh and strict, but in the posttest, they are tired and lenient, which changes the measurement standards. In this research design, the internal validity is compromised specifically by the threat of _____.

A researcher is evaluating a school program. Order the events to show how an undetected instrumentation threat leads a researcher to draw an invalid evaluative conclusion about a program's effectiveness.

Control Group in Pretest-Posttest Designs

Example of Regression to the Mean

In a research study, what condition primarily makes regression to the mean a severe threat to internal validity?

If a researcher specifically selects participants for an intervention because they scored in the extreme bottom 5% on a pretest, any subsequent improvement on their posttest scores can be confidently attributed solely to the effectiveness of the intervention.

A researcher is studying the impact of a new intensive reading program. Arrange the following steps in the correct order to illustrate how 'regression to the mean' acts as a severe threat to the internal validity of this study.

An educational researcher identifies the 30 students with the highest math-anxiety scores in a school and has them practice mindfulness for one week. On the posttest, their average anxiety scores have dropped significantly. Match each component of this research scenario to the specific role it plays in creating a threat to internal validity.

As a lead researcher, you are tasked with designing a new study to test an intervention for individuals experiencing extreme bouts of insomnia. To ensure the final results are not confounded by regression to the mean, arrange the following procedural steps in the order required to construct a valid experimental design.

According to the principle of regression to the mean, if participants are selected for a study specifically because they achieved exceptionally high pretest scores, what is the most likely statistical outcome for their posttest scores?

A researcher concludes that a new study-skills workshop is successful because the students who scored in the bottom $5\%$ on the first quiz showed a significant improvement on the second quiz. To evaluate the internal validity of this conclusion, one must account for the fact that these extreme scores were statistically likely to move closer to the group average due to _____ to the mean.

A researcher measures depressive symptoms in college students and recruits only the top $10\%$ most depressed students to participate in a new mindfulness intervention. At the end of the semester, the students' depressive symptoms decrease. In this design, regression to the mean is a major threat to internal validity because these participants were selected based on their extreme initial scores.

Match the pretest score scenario with its corresponding posttest tendency or statistical explanation under the threat of regression to the mean.

A clinical psychologist evaluates a new therapy for anxiety. She selects the $15$ patients with the highest anxiety scores from a clinic. After ten sessions of therapy, their anxiety scores decrease significantly. To evaluate the internal validity of this study, we must recognize that because participants were chosen for their extreme scores, the improvement is confounded by statistical _____.

Posternak and Miller's 2001 Spontaneous Remission Study

Control Group in Pretest-Posttest Designs

Wait-List Control Condition

Eysenck's 1952 Psychotherapy Effectiveness Study

Example of Spontaneous Remission

In psychological research, what does the term 'spontaneous remission' refer to?

Arrange the following stages to demonstrate how spontaneous remission can act as a confounding variable in a study that tracks only one group of participants.

A researcher finds that a group of patients with mild depression show significant improvement after 10 weeks of 'nature walking' therapy. If the researcher concludes the therapy was effective based on a study that lacked a control group, they are failing to account for the possibility of spontaneous remission.

A psychologist is evaluating a new therapy for anxiety and must account for spontaneous remission in their analysis. Match each experimental component to the logical role it plays in distinguishing the therapy's effect from natural recovery.

Spontaneous remission refers to the natural tendency for many medical and psychological conditions to improve over time without any formal treatment or intervention.

When evaluating a treatment using a one-group pretest-posttest design, how does spontaneous remission specifically threaten the study's internal validity?

When evaluating the results of a study that lacks a comparison group, a researcher who attributes a patient's improvement solely to a specific therapy may be making a flawed judgment by failing to rule out _____, which is the natural tendency for conditions to improve over time without any intervention.

A clinical trial evaluates a new therapy for depression using a one-group pretest-posttest design. Match each scenario component to the correct psychological research concept it represents.

When analyzing the internal validity of a clinical study that lacks a control group, a researcher realizes that participants' symptoms would have naturally improved on their own over time. In psychological research, this natural improvement without formal treatment is called _____.

A researcher claims a new mindfulness app reduces anxiety because a group of users reported lower anxiety after 4 weeks. Evaluate the validity of this claim by ordering the steps required to determine if spontaneous remission is a confound.