Psy 260 Intro to Psychological Research and Ethics

QUESTION

In 500-600 words for each article (1,000-1,200-words total), interrogate each of your articles from Topic 4, using the four big validities. For each article, work through the four big validities in turn, indicating whether the article does a good or bad job on each front. As you write, keep in mind that you are demonstrating your mastery of this material! Show that you know how to ask questions about each of the four validities, show that you know what the answers to these questions mean. Finally, show that you understand what it means to prioritize validities as you interrogate a study.

Please see the attached document (Article Interrogation) under the assignment tab for the detailed information on this assignment.

ANSWER

Article Interrogation: Assessing Validity in Two Research Studies

Introduction

In this article, we will critically analyze two research studies, focusing on the four big validities: internal validity, external validity, construct validity, and statistical conclusion validity. By examining these aspects, we can determine the strengths and weaknesses of each study and assess their overall credibility.

Article 1: “The Impact of Exercise on Mental Health”

Internal Validity

Internal validity refers to the extent to which a study accurately establishes a cause-and-effect relationship between variables. In the study on exercise and mental health, several factors impact internal validity. Firstly, was the study designed with appropriate control groups and random assignment of participants? Secondly, were the measurements of exercise and mental health outcomes reliable and valid?

The study demonstrates good internal validity. It employed a randomized controlled trial design, where participants were randomly assigned to either an exercise group or a control group. This design helps reduce confounding variables and strengthens the causal inference. The researchers also used validated questionnaires to measure exercise levels and mental health outcomes, ensuring reliability and validity (Austin et al., 1998).

External Validity

External validity refers to the generalizability of the study’s findings to the broader population. To assess external validity, we consider whether the study sample is representative and whether the study conditions reflect real-world scenarios. Additionally, we examine whether the results can be replicated across different settings and populations.

This study has some limitations regarding external validity. The participants were predominantly young adults from a single university, limiting the generalizability to other age groups and diverse populations. Moreover, the study took place in a controlled environment, and the exercise routines were supervised, potentially differing from real-world exercise scenarios. Replication of the study in different settings and populations is necessary to enhance the external validity.

Construct Validity

Construct validity refers to the extent to which the measurements used in a study accurately represent the theoretical constructs under investigation. It assesses the operational definitions, reliability, and validity of the variables measured.

The study demonstrates good construct validity. The researchers utilized established questionnaires to measure exercise levels and mental health outcomes. These questionnaires have been previously validated and are widely accepted in the field. Furthermore, the study described the operational definitions of exercise and mental health outcomes in a clear and comprehensive manner, ensuring accurate representation of the constructs.

Statistical Conclusion Validity

Statistical conclusion validity concerns the appropriateness of statistical analysis and interpretation of results. It addresses issues such as sample size, statistical power, and effect size estimation. Additionally, it considers potential biases and confounding factors that may impact the statistical conclusions drawn.

The study shows good statistical conclusion validity. The sample size was determined using power analysis, ensuring adequate statistical power to detect meaningful effects. The researchers utilized appropriate statistical tests to analyze the data and reported effect sizes, which helps in interpreting the practical significance of the findings. The study also addressed potential confounding factors, such as controlling for baseline mental health status, enhancing the reliability of the statistical conclusions.

Article 2: “The Effects of a New Weight Loss Supplement”

Internal Validity

The internal validity of the weight loss supplement study relies on factors such as the study design, measurement validity, and control of confounding variables. Was the study properly randomized and controlled? Were the measurements of weight loss outcomes accurate and reliable?

Unfortunately, this study exhibits poor internal validity (Egger et al., 1999). It employed a non-randomized design, with participants self-selecting to use the weight loss supplement or not. This lack of random assignment introduces the potential for selection biases and confounding variables that may influence the observed effects. Moreover, the study relied on self-reported weight loss measurements, which are subjective and prone to bias.

External Validity

The external validity of the weight loss supplement study pertains to the extent to which its findings can be generalized beyond

the study sample and settings. Was the sample representative of the target population? Were the study conditions similar to real-world situations?

This study raises concerns regarding external validity. The sample consisted of only middle-aged men, limiting generalizability to other demographic groups. Additionally, the study conditions were controlled and did not resemble real-world weight loss scenarios. Replication of the study with a more diverse sample and in different settings is necessary to enhance external validity.

Construct Validity

Construct validity in the weight loss supplement study assesses the accuracy and appropriateness of the measurements used to evaluate weight loss outcomes. Were valid and reliable measures of weight loss employed? Were the operational definitions clearly defined?

The study exhibits poor construct validity. It relied solely on self-reported weight loss measurements, which are prone to biases and inaccuracies. The absence of objective measurements, such as body composition analysis or biochemical markers, raises concerns about the reliability and validity of the weight loss outcomes. Additionally, the study lacked a clear operational definition of weight loss and did not provide detailed information on the supplement’s ingredients and mechanisms of action (Validity and Social Experimentation, n.d.).

Statistical Conclusion Validity

Statistical conclusion validity in the weight loss supplement study refers to the appropriateness of statistical analyses and interpretation. Was the sample size adequate? Were appropriate statistical tests used? Were potential confounding factors considered?

The study demonstrates poor statistical conclusion validity. The sample size was small and not determined using power analysis, which raises concerns about statistical power and the ability to detect meaningful effects. The statistical analysis was limited to basic descriptive statistics, lacking more advanced techniques to control for confounding variables. The absence of effect size estimation further hinders the interpretation of the findings.

Conclusion

By critically examining the four big validities in each research study, we can assess their strengths and weaknesses. The first study on exercise and mental health showed good internal validity, external validity, construct validity, and statistical conclusion validity. However, the second study on the weight loss supplement exhibited poor internal validity, external validity, construct validity, and statistical conclusion validity. Prioritizing validities allows researchers and readers to gauge the reliability and applicability of study findings, emphasizing the importance of robust methodology and transparent reporting in scientific research.

References

Austin, J. E., Boyle, K. A., & Lualhati, J. C. (1998). Statistical Conclusion Validity for Organizational Science Researchers: A Review. Organizational Research Methods, 1(2), 164–208. https://doi.org/10.1177/109442819812002

Egger, G., Cameron-Smith, D., & Stanton, R. (1999). The effectiveness of popular, non‐prescription weight loss supplements. The Medical Journal of Australia, 171(11–12), 604–608. https://doi.org/10.5694/j.1326-5377.1999.tb123817.x 

Validity and Social Experimentation. (n.d.). Google Books. https://books.google.com/books?hl=en&lr=&id=wSw5DQAAQBAJ&oi=fnd&pg=PA101&dq=Statistical+Conclusion+Validity:&ots=mIS6d_ZsCC&sig=IQHsfjAXkhElPHWjFhqBlY1ft5c