PS300 Unit 4 Evaluating Conclusions Paper Example

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A local headline claiming that smartphones are killing pedestrians is tested against the evidence in this PS300 Unit 4 paper evaluating conclusions. Nasar and Troyer's emergency department data show phone-related pedestrian injuries rising through 2010, and Thompson and colleagues' observation links texting to unsafe crossing, but coding changes, more walkers with phones, and differences between texters and others mean neither design shows cause. Internal and external validity are applied to each study, convergence is credited, and the paper proposes a more accurate headline. Purdue Global PS 300, Research Methods I, assigns this paper in the BS in Psychology course. The paper treats evaluation as a skill a reader can practice on any news story.

CoursePS300 Research Methods I
UnitUnit 4
Paper typeEvaluating conclusions paper
LengthAbout 500 words, 4 pages double-spaced
FormatAPA 7 student paper
SchoolPurdue University Global
ProgramBS in Psychology
UpdatedOctober 2026

Free sample paper for PS300 Unit 4

1

Do Phones Kill Pedestrians? A PS300 Unit 4 Paper Evaluating a Headline's Conclusion

[Student Name]

Purdue University Global

PS300: Research Methods I

Unit 4 Evaluating Conclusions Paper

[Instructor Name]

[Date]

The headline and news article are composite; the studies evaluated are real.

What this part is doingStating the headline, the evidence and the narrower supported claim in the lead shows the paper reaches a judgment.
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The Claim

A local news story carried the headline "Smartphones are killing pedestrians." It reported a rise in pedestrian deaths in the state over several years, quoted a police officer who had seen people walk into traffic while looking at phones, and cited research. The causal claim is in the headline: phones cause pedestrian deaths.

Evidence One: Emergency Room Records

Nasar and Troyer (2013) used national emergency department data from 2004 through 2010 and found that injuries to pedestrians related to mobile phone use increased relative to all pedestrian injuries, and by 2010 exceeded those for drivers. This supports the claim that phone-related pedestrian injuries were growing. It does not show that phones caused the injuries, because the records depend on how hospital staff coded each case, and coding of phone involvement may have changed as phones became a topic of concern. Rising numbers of people walking while owning phones could also raise counts without any change in risk per person.

Evidence Two: Observation at Intersections

Thompson et al. (2013) observed 1,102 pedestrians and found that texting pedestrians were 3.9 times as likely as undistracted pedestrians to cross unsafely. That is a strong association. Because the study observed rather than assigned texting, the texters may differ in other ways, such as age, hurry or general risk-taking. The authors adjusted for age and gender, which helps, but other differences remain possible.

A strong association is not the same as a cause, and both studies, by design, measure association.

Validity, Applied

The first kind of validity, internal, asks whether a study's results reflect the variables of interest rather than other explanations. Both studies have limited internal validity for causal claims, because neither manipulated phone use. External validity concerns whether findings generalize. The emergency room data are national but older; the observational study is recent for its time but from one city. Cozby and Bates (2020) note that convergent evidence from different designs strengthens a conclusion even when each design alone is limited, and these two studies do converge.

What this part is doingApplying internal and external validity to each study shows the terms used as tools, not definitions.
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A Narrower Claim

Taken together, the studies back a smaller claim than the headline makes. Phone use while walking is associated with unsafe crossing behavior and with a growing share of pedestrian injuries, and it is plausible that phones contribute through distraction, consistent with research showing that phone users notice less of their surroundings. The evidence does not show that phones are the main cause of the rise in pedestrian deaths, which also reflects changes in vehicle size, road design and the number of people walking.

A Better Headline

A more accurate headline would be: "Phone use while walking tied to riskier crossing, studies find." It is less dramatic, but it matches what the designs can show.

What this part is doingRewriting the headline turns the evaluation into a concrete, testable correction.
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References

Cozby, P. C., & Bates, S. C. (2020). Methods in behavioral research (14th ed.). McGraw-Hill Education.

Nasar, J. L., & Troyer, D. (2013). Pedestrian injuries due to mobile phone use in public places. Accident Analysis & Prevention, 57, 91-95. https://doi.org/10.1016/j.aap.2013.03.021

Thompson, L. L., Rivara, F. P., Ayyagari, R. C., & Ebel, B. E. (2013). Impact of social and technological distraction on pedestrian crossing behaviour: An observational study. Injury Prevention, 19(4), 232-237. https://doi.org/10.1136/injuryprev-2012-040601

PS300 Unit 4 instructions, in plain terms

In Unit 4, PS300 often asks whether a study's or news story's conclusion follows from its evidence. Identify the claim precisely, noting whether it is causal. Examine each piece of evidence offered for it by its design, explaining what that design can and cannot support. Apply internal and external validity to each study rather than defining them in the abstract. Consider alternative explanations, such as third variables, reverse direction or changes in how data were recorded. Assess whether different studies converge. Conclude with the claim the evidence actually supports, stated as carefully as the evidence allows. Cite the original studies, not only the news article, and avoid swinging from accepting the headline to dismissing the research entirely.

Inside the PS300 Unit 4 example

The paper quotes the headline and identifies its causal claim. The emergency department study is described with its years and finding, then questioned on coding practices and exposure. The intersection study is described with its 3.9 times figure and questioned on unmeasured differences, under a highlighted line that both designs measure association. A section applies internal validity to the lack of manipulation and external validity to age and place, and credits convergence with Cozby and Bates. The supported claim is stated as an association and a plausible contribution, alongside vehicle size and road design. A rewritten headline closes the paper. Each study gets the same three questions: what was measured, what the design permits and what else could explain the result.

Reading the PS300 Unit 4 grading rubric

Instructors grade this unit on precise reasoning about claims and designs. Papers earn credit for identifying the type of claim, tracing each piece of evidence to its design and naming specific alternative explanations. Validity concepts score best when applied to the actual studies. Recognizing that convergent evidence from different designs strengthens a conclusion shows sophistication. The final claim should be neither the original headline nor a blanket dismissal, but a carefully worded statement the evidence supports. Using the original studies rather than the news summary is expected. Clear organization and accurate citations complete the paper. Proposing a corrected claim, as the headline rewrite does, shows the evaluation can produce something useful.

Common PS300 Unit 4 mistakes, and how to avoid them

The most frequent error dismisses the research because it is correlational, rather than stating what it does show. Another accepts the headline because the studies found an association. Students often define validity terms without applying them. Alternative explanations tend to be generic, such as other factors, without naming one. Some papers rely on the news article's description of the studies, which may be inaccurate. Before submitting, label the original claim as causal or not, name one specific alternative explanation for each study, apply both validity types to each and write the claim you think the evidence supports in one sentence. That sentence is the heart of the paper.

Get a PS300 Unit 4 example written to your instructions

Share the claim or study and the instructions with the rubric. A custom paper checks validity and the fit between design and conclusion. It arrives within 24-48h; first requests are free. The paper above is an original model document written by our desk, not a submitted student paper and not an official Purdue University Global document.

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PS300 Unit 4 questions, answered

What is internal validity?

Confidence that a study's results reflect the variables studied and not other explanations.

What is external validity?

How well the results generalize to other people, settings and times.

Why is correlation not causation?

A third variable or reverse direction could explain the association.

Where can I find a free PS300 Unit 4 sample paper?

The full PS300 Unit 4 paper is on this page, testing a headline about phones and pedestrian deaths against two published studies.

What headline does the PS300 Unit 4 sample propose?

Phone use while walking tied to riskier crossing, studies find, which matches what the designs can show.