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 a

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.

Describe the key characteristics of a one-group pretest-posttest design and explain why the order of conditions cannot be counterbalanced in this specific design.

Based on the characteristics of a one-group pretest-posttest design, explain why the school psychologist's conclusion is difficult to make with certainty. What specific feature is missing from this study design that makes it vulnerable to alternative explanations?

A researcher wants to study the effect of a new anti-bullying curriculum using a one-group pretest-posttest design. Briefly describe the exact sequence of steps the researcher must take to measure the dependent variable (students' attitudes toward bullying) and administer the treatment according to this specific quasi-experimental design.

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 externa

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 int

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.

Describe the concept of 'history' as a threat to internal validity. In your explanation, define what history threats are, specify when they must occur relative to the study's measurements, and explain how they impact the interpretation of changes in the dependent variable.

Based on this scenario, diagnose why the celebrity drug overdose constitutes a history threat to internal validity. How does this event compromise the researchers' ability to evaluate the anti-drug program's effectiveness?

A researcher plans to evaluate a new psychology teaching method using a one-group pretest-posttest design, but is concerned that external campus events during the semester will act as a history threat. What design modification should they apply to control for this threat, and why does this modification work?

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.

Define maturation as a threat to internal validity and provide at least three examples of natural changes that can occur between pretest and posttest measurements in a study.

Based on the concept of maturation as a threat to internal validity, diagnose why the researcher's conclusion might be flawed and explain what alternative factor could account for the observed differences.