HSRT Evaluating Scientific Evidence 2

Question 1

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?

Accepted Answer

The absolute risk reduction suggests the clinical benefit may be modest

Answer

The treatment is highly effective based on relative risk alone

Answer

Relative and absolute risk reductions always agree in direction

Answer

A 50% relative risk reduction always justifies treatment

Question 2

Which component of an evidence hierarchy is typically considered the weakest form of clinical evidence?

Accepted Answer

Expert opinion

Answer

Systematic review

Answer

Randomized controlled trial

Answer

Cohort study

Question 3

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:

Accepted Answer

Very low because prevalence is low

Answer

Very high because sensitivity is high

Answer

Equal to the sensitivity value

Answer

Determined solely by specificity

Question 4

Researchers randomly assign participants to treatment and control groups. The primary purpose of randomization is to:

Accepted Answer

Control for all known and unknown confounders

Answer

Ensure an equal number of males and females

Answer

Guarantee blinding of participants

Answer

Eliminate attrition from the study

Question 5

A study is described as 'double-blind.' What does this mean?

Accepted Answer

Both participants and outcome assessors are unaware of group assignment

Answer

Both the funding agency and the journal are unaware of the results

Answer

Two independent researchers conducted the analysis

Answer

The study included two separate blinded control groups

Question 6

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:

Accepted Answer

The observed reduction may be due to chance; more data are needed

Answer

The program definitively does not work

Answer

Statistical significance confirms clinical effectiveness

Answer

The p-value proves the null hypothesis is true

Question 7

Which action is most important when critically appraising a research article's methodology?

Accepted Answer

Evaluating whether the study design is appropriate for the research question

Answer

Checking the prestige of the journal it was published in

Answer

Counting the number of references cited

Answer

Confirming the lead author's institutional affiliation