The study showed that the most effective method of getting the barman's attention is to "belly up" to the bar and turn towards the barman. In my own experience I find it hard at times to tell who is next, if there are a few spaces at the bar, someone will crowd in and complicate the process of determining who is actually next. The waiver I find to be very aggravating, usually they are the ones that have no respect for others and of the "Me" beliefs. Even if you take care of them out of sequence they rarely tip or even say "thanks". I tend to ignore a person waiving their hands behind several people that are patiently waiting their turns there is no gain, I really might even skip over them when it is actually their turn because the aggravated me. .
Germany, only 15 waived their wallets and 25 gestured to the barman. 90% were content to work their way up to the bar and watch the barman until they could be waited on. One of the other problems in a bar is that it is sometimes hard to distinguish between those who are just standing and talking and those that wish to be served. This is also complicated by the dim lighting, noise and multiple customers all competing for the attention of the barman. The process almost becomes a contest to see who can get the barman's attention first.
I try to keep the guests in the order that they arrive, but there are times especially when there is a large order that requires complicated cocktails to be made and a big crowd in the bar, I loose track of who is truly next. It is usually the body language that will get my attention next, but there might be a pretty lady that holds my eye as well. All I can say is that if you are a little patient, after all if you are in a bar on an island, you should be able to slow down to "Island Time" and enjoy the experience. Quality cocktails take a little more time, be patient, the wait is worthwhile for what you will receive. ;o)