The ratio between incidence among exposed and nonexposed persons is called-
Attributable risk
Positive predictive value
Relative risk
Odds ratio
.relative risk also called as risk ratio ,is the ratio of the incidence of the disease or death among exposed and incidence among non exposed.it is a direst measure of strength of association between suspected cause and effect.RR of one indicates no association,it must also be noted that risk does not necessarily imply causal association ref:park&;s textbook,ed22,pg no 75
Epidemiology