Evaluating Scientific Evidence Flashcards
7 cards from real HSRT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Evaluating Scientific Evidence flashcards as text
A clinical trial reports a relative risk reduction of 50% for a new treatment, but the absolute risk reduction is only 1%. Which statement best reflects the clinical significance?
Answer: The absolute risk reduction suggests the clinical benefit may be modest
An absolute risk reduction of 1% means treating 100 patients prevents one additional case, suggesting the benefit may be modest despite the impressive relative figure.
Which component of an evidence hierarchy is typically considered the weakest form of clinical evidence?
Answer: Expert opinion
Expert opinion sits at the bottom of evidence hierarchies because it is most susceptible to individual bias and lacks empirical rigor.
A diagnostic test has a sensitivity of 95% and a specificity of 60%. In a population with low disease prevalence, the positive predictive value will be:
Answer: Very low because prevalence is low
In low-prevalence populations, even highly sensitive tests yield many false positives, resulting in a low positive predictive value.
Researchers randomly assign participants to treatment and control groups. The primary purpose of randomization is to:
Answer: Control for all known and unknown confounders
Randomization distributes both known and unknown confounding variables equally across groups, strengthening causal inference.
A study is described as 'double-blind.' What does this mean?
Answer: Both participants and outcome assessors are unaware of group assignment
Double-blinding means neither participants nor the researchers assessing outcomes know who received the treatment, reducing performance and detection bias.
An article claims that a hospital's new hand-hygiene program reduced infection rates from 10% to 8%. The authors report this as statistically non-significant (p = 0.12). The most reasonable conclusion is:
Answer: The observed reduction may be due to chance; more data are needed
A non-significant p-value does not prove the null hypothesis; it means the data are insufficient to rule out chance as an explanation.
Which action is most important when critically appraising a research article's methodology?
Answer: Evaluating whether the study design is appropriate for the research question
The alignment between the study design and the research question is the foundational step in assessing methodological quality.