"Interviewing needs time, focus, and lots of preparation. If one is undertaking lots of interviews one after the other, one must allow some time between the interviews to make notes, scribble down certain key words as aides memoire, to ensure that differentiation between interviews can be maintained effectively. Always make sure that you know who you are about to interview, what the purpose of the interview is; refresh your mind by quickly scanning the background papers. I jest not but it has been known to happen that, only some way into the interview, an interviewer suddenly realised that the interview was being conducted with the wrong person.'
"Always stay awake! It is hard at times. Especially when one is involved in a crazy schedule of undertaking say six interviews in one day, one after another with little time between interviews. Or when one is interviewing straight after a long distance flight with all the effects of jet lag, dehydration etc. But if you are interviewing, it is your responsibility, and only your responsibility, to ensure that you are awake and alert; anything else would be the height of discourtesy to the interviewee. It does happen. It has happened to me when I was being interviewed. It is the only time that I can recall when someone interviewing me almost fell asleep, and as many will attest I am fairly animated when I speak. The interviewer happened to be the CEO of Korn Ferry International at the time, who had just arrived that morning from the States. He had a sudden attack of jet lag and was visibly on the verge of dropping off, in fact did drop off for what amounted to a few seconds. It has nearly happened to me, but as I am so very awake I take evasive action the moment I think I am entering the danger zone. (Evasive action includes drinking water, changing sitting position, becoming even more active listener, writing notes, even suggesting a natural break). Whatever it takes, but stay awake and alert!"
(pp. 90-1, 'It's the People: What really drives great management and leadership' by John A. Dembitz - Landmark)