Treatment efficacy contrast functions
TE(R0, R1)A vector of risks in the control arm
A vector of risks in the treatment arm
A vector the same length as R0 and R1.
These functions take the risk in the two treatment arms, and
computes a one-dimensional summary of those risks. Built-in choices are
"TE" for treatment efficacy = 1 - risk_1(s)/risk_0(s), "RR" for
relative risk = risk_0(s)/risk_1(s), "logRR" for log of the relative
risk, and "RD" for the risk difference = risk_0(s) - risk_1(s).