Statistics Flashcards
Phase I trial
Dose escalation for optimal drug dose and route, & assess safety in humans, .
Phase II trial
Efficacy evaluation, further assess safety. Compare to standard treatment for safety and efficacy.
Phase III trial
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.
Phase IV trial
Long term outcomes assessed in various populations and side effects.
Sensitivity (Sn)
TP / TP+FN
Specificity (Sp)
TN / TN+FP
Positive Predictive Value (PPV)
TP / TP+FP
Negative Predictive Value (NPV)
TN / TN+FN
Positive Likelihood Ratio (+LR)
Sn / 1-Sp
“probability of positive result and having disease compared to no disease”
Negative Likelihood Ratio (-LR)
1-Sn / Sp
“probability of negative result and having disease compared to no disease”
Number needed to treat (NNT)
1 / (absolute risk or rate reduction)
Acceptable drop out rate in trials
More than 20% drop out considered poor quality study.
Pretest odds
Pretest probability / (1 - pretest probability)
Posttest probability
Posttest odds / (posttest odds + 1)