Statistics

Question 1

Phase I trial

Answer 1

Dose escalation for optimal drug dose and route, & assess safety in humans, .

Question 2

Phase II trial

Answer 2

Efficacy evaluation, further assess safety. Compare to standard treatment for safety and efficacy.

Question 3

Phase III trial

Answer 3

Survival benefits compared with current standard of care for a specific disease. Off label use if prescribed and shown in peer reviewed trials, but not approved.

Question 4

Phase IV trial

Answer 4

Long term outcomes assessed in various populations and side effects.

Question 5

Sensitivity (Sn)

Answer 5

TP / TP+FN

Question 6

Specificity (Sp)

Answer 6

TN / TN+FP

Question 7

Positive Predictive Value (PPV)

Answer 7

TP / TP+FP

Question 8

Negative Predictive Value (NPV)

Answer 8

TN / TN+FN

Question 9

Positive Likelihood Ratio (+LR)

Answer 9

Sn / 1-Sp

“probability of positive result and having disease compared to no disease”

Question 10

Negative Likelihood Ratio (-LR)

Answer 10

1-Sn / Sp

“probability of negative result and having disease compared to no disease”

Question 11

Number needed to treat (NNT)

Answer 11

1 / (absolute risk or rate reduction)

Question 12

Acceptable drop out rate in trials

Answer 12

More than 20% drop out considered poor quality study.

Question 13

Pretest odds

Answer 13

Pretest probability / (1 - pretest probability)

Question 14

Posttest probability

Answer 14

Posttest odds / (posttest odds + 1)