|The BTL Procedure|
If you do not specify a REPEATED statement, the WEIGHT statement operates exactly like the one in PROC GLM. In this case PROC BTL replaces and with and , where is the diagonal weight matrix. If you specify a REPEATED statement, then the WEIGHT statement replaces with , where is a diagonal matrix with elements . Observations with nonpositive or missing weights are not included in the PROC BTL analysis.
Note: This procedure is experimental.