HSRT Assessing Credibility of Claims 3

Question 1

A health claim states: 'Nine out of ten doctors recommend our supplement.' Which credibility problem is MOST directly illustrated by this statement?

Accepted Answer

Lack of specification — which doctors, how many, what question was asked, and who funded the survey are all unknown

Answer

A credible statistical claim requires specification of the sample, methodology, and funding. Without these details, the statistic is unverifiable.

Question 2

A nursing professor tells students: 'I've been practicing for 30 years and I've never seen a patient harmed by that medication.' This claim should be assessed with which critical lens?

Accepted Answer

Personal clinical experience, however extensive, is not a substitute for systematic evidence and can be subject to survivorship bias

Answer

Even extensive personal experience is subject to survivorship bias, recall bias, and is inferior to controlled systematic studies when assessing drug safety.

Question 3

A medical journal publishes a randomized controlled trial with a p-value of 0.049. A subsequent letter argues the result is not credible because the pre-specified primary outcome was changed after data collection. This argument MOST directly challenges:

Accepted Answer

Internal validity — outcome switching inflates false-positive rates and undermines the statistical credibility of the finding

Answer

Post-hoc outcome switching (HARKing) inflates the false-positive rate and directly undermines the internal validity and credibility of the reported p-value.

Question 4

A pharmaceutical sales representative presents a graph showing that patients on their drug lived on average 2.1 months longer. The survival benefit was statistically significant (p=0.001). Which credibility question is MOST important?

Accepted Answer

Is 2.1 months of additional survival clinically meaningful given the drug's side effects and cost?

Answer

Statistical significance does not equal clinical significance. A 2.1-month benefit must be weighed against quality of life, side effects, and cost to assess real-world credibility.

Question 5

A public health official states: 'Since we introduced the vaccine campaign, hospitalizations fell by 45%, proving the vaccine works.' Which credibility flaw is MOST apparent?

Accepted Answer

Post hoc ergo propter hoc — assuming causation from temporal sequence without controlling for other factors

Answer

Temporal precedence alone does not establish causation. Other concurrent factors (seasonal variation, herd immunity, behavior changes) may have contributed to the decline.

HSRT - Health Sciences Reasoning Test Practice Test

HSRT - Health Sciences Reasoning Test Practice Test

HSRT Assessing Credibility of Claims 3