QuestionSBA
QuestionChoice
This is incorrect as the horizontal line on a forest plot indicates the confidence intervals as opposed to the range of the data sets. A wide confidence interval indicates instability of results, for example, due to a very small data set
32554
b
James et al. have the largest range of results
QuestionChoice
This is false as all of the forest plot lines are above 1. In risk ratios or relative risk, if the ratio is >1, then this means that the intervention has a less favourable risk than in the group not subject to the intervention, i.e. greater risk of hernia recurrance.
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e
All the studies suggest that her method has a lower risk of hernia recurrence
QuestionChoice
This is incorrect as the horizontal line is a representation of the confidence intervals. A wide confidence interval is more likely to be representative of a smaller data set
32556
d
James et al. likely had the most participants in their study
QuestionChoice
This is true as all of the forest plot lines are at or above 1. In risk ratios or relative risk, if the ratio is >1, then this means that the intervention has a less favourable risk than in the group not subject to the intervention, i.e. greater risk of hernia recurrance.
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a
None of the studies suggest that her method has a lower risk of hernia recurrence
QuestionChoice
This is incorrect as the ratio here is very close to 1, indicating that the risk of recurrence from her technique is very similar to the risk of recurrence from other techniques
32555
c
Edwards et al. show the biggest difference in the risks of hernia recurrence between her technique and other techniques
QuestionComment
No because Edwards et al has a range from below 1 to above 2
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BradySclerosis
QuestionComment
also shade on the colleague
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User
subscriber
BradySclerosis
Concept
Chapter
# Definition 

A type of clinical study in which participants are assigned to groups that receive one or more intervention/treatment (or no intervention) so that researchers can evaluate the effects of the interventions on biomedical or health-related outcomes.

# Types of interventional trials 

A randomized control trial is the strongest type of interventional trial, but other forms include non-randomised controlled trials, pre-post studies and quasi experiments.

A pre-post study is a study in which occurrence of an outcome is measured both before and after an intervention is administered; it is in this way that the effect of the intervention can be properly assessed. If the occurrence of the outcome was only measured after the intervention; the exact effect of the intervention cannot be determined.

Another form of trial is a crossover randomized control trial. A crossover RCT is a type of interventional study design where study participants intentionally “crossover” to the other treatment arm.

# Uses 

Interventional studies are used to answer study questions relating to either therapeutic agents, and evaluating the efficacy of therapeutic agents, or are used to assess mechanisms of preventing potential causes of damage.
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Interventional studies
Topic
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Medical Statistics
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A forest plot visually displays results from multiple studies, showing effect sizes with confidence intervals; points crossing the line of no effect indicate non-significance
Picture
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Forest Plot.jpg
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Topic
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Medical Statistics
Your colleague has a particular way of performing inguinal hernia repairs that is less commonly used. She wants to know whether her technique has a higher or lower rate of recurrence. She finds five studies that use her method compared to the routine method and plots them in a forest plot (x-axis represents the relative risk of recurrence in your colleague's method compared to the routine method).

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Which of these statements about her findings is true?
a