Presenting Clinical Trials

Question 1

What is a confidence interval?

Answer 1

It gives an estimated range of values which is likely to include an unknown population parameter. Describing the uncertainty of an estimate

Question 2

Narrow confidence intervals indicate?

Answer 2

A higher level of confidence

Question 3

Why are confidence values better than p values

Answer 3

1) Give a range of possible effect sizes,
2) Embrace the value of no difference between treatments,
3) Help interpret clinical trial data,
4) Statistically significant does not mean critically important!

Question 4

What does number-needed-to-treat mean?

Answer 4

Describes the difference between treatment and control in achieving a particular outcome

Question 5

Define relative risk?

Answer 5

It is the probability of an outcome if on drug / Possibility of an outcome if on placebo

Question 6

Define an odds ratio?

Answer 6

Odds that the diseased were exposed / Odds the controls were exposed

Question 7

In what studies do you use relative risk or odds ratio?

Answer 7

Relative risk - Cohort studies and clinical trials.

Odds ratio - Case control studies

Question 8

What is heterogenity?

Answer 8

The extend to which outcomes vary

Question 9

What is I^2?

Answer 9

The amount of variation not caused by sampling error