ev.bugs

model {
  for (i in 1:n) {
    y[i] ~ dbern(p.bound[i]);
    p.bound[i] <- max(0, min(1, p[i]));
    logit(p[i]) <- aff.a[i] - aff.b[i];
    aff.a[i] <- b.friend[country.a[i], giver[i]] + b.song[song.a[i]];
    aff.b[i] <- b.friend[country.b[i], giver[i]] + b.song[song.b[i]];
  }

  for (j in 1:n.countries) {
    for (k in 1:n.countries) {
      b.friend[j, k] ~ dnorm(0, tau.friend);
    }
  }
  for (l in 1:n.songs) {
    b.song[l] ~ dnorm(0, tau.song);
  }
  
  tau.friend <- pow(sigma.friend, -2);
  tau.song <- pow(sigma.song, -2);
   
  sigma.friend ~ dunif(0, 1000);
  sigma.song ~ dunif(0, 1000);
}