Risk Reduction Calculator

Given information about the probability of an outcome under control and experimental treatments, this calculator produces measures of risk increase/decrease and number needed to treat or harm, including confidence intervals. If some patients were lost to follow-up, the calculator provides estimates for several different scenarios.

Enter your data in one of these ways:

Numbers of patients who experience good and bad outcomes
under the new therapy and control therapy:

			Lost to follow-up (optional)


Total	0	0	0

or
Type of event and event rates (and, optionally, sample size):

The events I'm interested in are:
Control event rate:	%
Experimental event rate:	%
Optional
Total # of patients in control group:
# of patients in control group lost to follow-up:
# of patients in experimental group:
# of patients in experimental group lost to follow-up:

Printing options

If you'd like to produce an annotated printable version of the results you've computed above, fill out the optional fields below, and click "Printable version"

Optionally, provide a title for the output (such as the article citation):

Optionally, provide a block of text to appear in the printable output, on the left side:

Optionally, provide a block of text to appear in the printable output, on the right side:

Embeddable url: http://ulan.mede.uic.edu/cgi-bin/nntcalc.pl?2x2=Compute