Examples of Experimental, Quasi-Experimental, and Nonexperimental Research

Experimental Research

Title: The Effects of a Mindfulness Meditation Intervention on Stress and Anxiety in College Students

Authors: Jain, N., et al. (2015)

Journal: Journal of American College Health

Research Design: Randomized controlled trial (RCT)

Summary: This study investigated the efficacy of a mindfulness meditation intervention in reducing stress and anxiety among college students. Participants were randomly assigned to either a mindfulness meditation intervention group or a control group. The mindfulness meditation group participated in weekly meditation sessions for eight weeks, while the control group received no intervention. The results showed that the mindfulness meditation intervention significantly reduced stress and anxiety symptoms compared to the control group.

Key Features of Experimental Research:

• Manipulation of independent variable: The researchers manipulated the independent variable, which was the mindfulness meditation intervention.
• Random assignment of participants: Participants were randomly assigned to either the treatment group or the control group. This helps to control for confounding variables and ensure that the observed effects are due to the intervention, rather than other factors.
• Control group: The inclusion of a control group allows the researchers to compare the effects of the intervention to a group that did not receive the intervention.

Quasi-Experimental Research

Title: The Relationship between Physical Activity and Academic Performance in Adolescents

Authors: Sallis, J. F., et al. (2001)

Journal: Pediatrics

Research Design: Cross-sectional study

Summary: This study examined the relationship between physical activity levels and academic performance in adolescents. The researchers collected data on physical activity levels and academic performance from a large sample of adolescents. The results showed that adolescents who engaged in more physical activity had higher academic performance compared to those who were less active.

Key Features of Quasi-Experimental Research:

• Manipulation of independent variable: The independent variable, which was physical activity levels, was not manipulated by the researchers. Instead, the researchers observed the natural variation in physical activity levels among the participants.
• No random assignment: Participants were not randomly assigned to different levels of physical activity. This means that there may be confounding variables that could explain the relationship between physical activity and academic performance.

Nonexperimental Research

Title: The Impact of Social Support on Mental Health among Older Adults

Authors: Choi, H. C., et al. (2008)

Journal: Aging & Mental Health

Research Design: Correlational study

Summary: This study examined the relationship between social support and mental health among older adults. The researchers collected data on social support levels and mental health symptoms from a large sample of older adults. The results showed that older adults with higher levels of social support had better mental health compared to those with lower levels of social support.

Key Features of Nonexperimental Research:

• No manipulation of variables: The researchers did not manipulate any variables in this study. Instead, they observed the natural variation in social support and mental health symptoms among the participants.
• No random assignment: Participants were not randomly assigned to different levels of social support. This means that there may be confounding variables that could explain the relationship between social support and mental health.

Evaluation of Research Designs

Experimental Research Example:

The mindfulness meditation intervention study is an example of a well-designed experimental study. The researchers manipulated the independent variable, randomly assigned participants to groups, and included a control group. This design strengthens the internal validity of the study, meaning that the researchers can be more confident that the observed effects are due to the mindfulness meditation intervention.

Quasi-Experimental Research Example:

The physical activity and academic performance study is an example of a quasi-experimental study. The researchers did not manipulate the independent variable or randomly assign participants to groups. This limits the internal validity of the study, making it more difficult to determine whether the observed relationship between physical activity and academic performance is causal.

Nonexperimental Research Example:

The social support and mental health study is an example of a nonexperimental study. The researchers did not manipulate any variables or randomly assign participants to groups. This further limits the internal validity of the study, making it even more difficult to determine whether the observed relationship between social support and mental health is causal.

Conclusion

Experimental, quasi-experimental, and nonexperimental research designs all have strengths and weaknesses. Experimental research designs are the strongest because they allow researchers to make causal inferences. However, not all research questions can be answered using an experimental design. Quasi-experimental and nonexperimental research designs can be