Why do some items differ between the ASR and ABCL versions of a syndrome scale, such as the Anxious/Depressed scale?

Answer: As explained in Chapter 7, the ASR and ABCL scales for scoring some syndrome constructs differ because (a) some items that are unique to one instrument were found to load on the version of a syndrome derived from that instrument and are therefore included in the scale for scoring the syndrome from that instrument; (b) some items that have counterparts on both instruments were nevertheless found to load on the version of a syndrome that was derived from only one instrument. Most items of the syndrome scales are common to both instruments, but the items that are specific to one instrument on some scales may improve measurement of syndrome constructs by that instrument.