riskdifference {fmsb}R Documentation

Calculate risk difference and its confidence intervals

Description

Calculate risk difference (a kind of attributable risk / excess risk) and its confidence intervals based on approximation, followed by null hypothesis (risk difference equals to 0) testing.

Usage

 riskdifference(a, b, N1, N0, CRC=FALSE, conf.level=0.95) 

Arguments

a

The number of disease occurence among exposed cohort.

b

The number of disease occurence among unexposed cohort.

N1

The population at risk in exposed cohort.

N0

The population at risk in unexposed cohort.

CRC

Logical. If TRUE, this function also calculates the risks for each cohort and for both combined, with confidence intervals. Default FALSE.

conf.level

Probability for confidence intervals. Default is 0.95.

Value

estimate

Calculated point estimate of risk difference.

conf.int

A numeric vector of length 2 to give upper/lower limit of confidence intervals.

p.value

The significant probability of the result of null-hypothesis testing.

Author(s)

Minato Nakazawa (minato-nakazawa[atmark]umin.net)

Reference(s)

Rothman KJ (2012) Epidemiology: An Introduction. 2nd Ed., Oxford University Press, Oxford.

Examples

 res <- riskdifference(321, 411, 686, 689, CRC=TRUE)
 str(res)
 print(res)

[Package fmsb Index]