for sd(_cons), sigma=1.101636, se(sigma)=.0682399, the z-statistic can be estimated by
log(sigma) / (se(sigma)/sigma) , and p-value for testing ln(sigma)=0 or sigma=1 is
the H0 test for sigma is if log(sigma)=0 or sigma=1. 0 is the lower boundary of sigma. So we don't use p-value for testing if sigma=0. The LR test is significant, from that, the conclusion is we cannot reject there is no random effect from hid.