8.4  Blood: indirect comparisons 
 
#  Monitor    AvsB		sigma		theta	mu.phi     tau.phi	
	
model{
for(i in 1:I){
          x[i] ~  dnorm(mu[i],prec[i])
         mu[i] <- theta[treat[i]] + phi[study[i]]
       prec[i] <- n[i]/(sigma*sigma)
#                     could do in terms of t's if assumed different sigma's
         SS[i] <- s[i]*s[i]*(n[i]-1)
         SS[i] ~  dgamma(a[i],b[i])
          a[i] <- (n[i]-1)/2
          b[i] <- 1/(2*sigma*sigma)
}
for(j in 1:J){                         #  random study effects
        phi[j] ~ dnorm(mu.phi, inv.tau2.phi)
}
#                                       contrasts of interest
      AvB  <- theta[2]-theta[3]
#  priors
     mu.phi ~ dunif(-50,50)
  inv.tau2.phi  <- 1/(tau.phi*tau.phi)
      tau.phi ~ dunif(0,100)
    log(sigma) <-logsigma
     logsigma~dunif(-10,10)
       theta[1]  <- 0
for(k in 2:4){
        theta[k] ~ dunif(-50, 50)
}


}