RCT Simulator:SimTrial

(ver. 0.9b)programmed by T. Fukuoka

What you can do in this page: You can set the true effect of a treatment, and then you can see what will happen in your planned clinical trial.

How to do it: At first, please set true event rate (mortality rate, admission rate or mobidity rate etc.) of two treatment modalities (ordinary one and new one). Then you can plan a clinical trial (patient number of each group). Push the "Start" button and you can see a result of you trial.

How to enjoy: 1. Set event rates according to a acutual clinical trial and push the button several times.

How to enjoy: 2. Set same event rates (Say, 0.2) and push the button several times to see the variation of the results.


Please set two event rates

Put the number between 0 and 1. 10%→0.1, 1%→0.01

Event rate of ordinary treatment

Event rate of new treatment

 Event rate→Mortality, morbidity or admission rate.


Decide the patient number of clinical trial

Caution:If you set number more than 100, it will take several seconds. If you are willing to wait several minutes, you can set patient number more than 1000.

Patient number of ordinary treatment

Patient number of new treatment


Push the start bottun, and you will find the result.

If you push it again, you will get another result


Result of your trial

The event rate of ordinary group is .

The event rate of new treatment group is .

Absolute risk reduction is .

Risk ratio is .

Absolute risk reduction is the acutual difference of event rates between the groups. If the effect of the new treatment is same, it will be "O".

Risk ratio is the fraction of event rates of the groups. If the effect of the new treatment is same, it will be "1".