My friend and former colleague, Andre Vazhnov, has a tendency of randomly throwing out some thought-provoking statements. Last night he asked me what I thought about multitasking. While being an effective multitasker seems to be a requirement for every other job, and by Andre's measure, nearly every candidate he interviews claims to be good at multitasking, he claims he's never seen it working well in practice. Further, he states, the term is severely generalized if not misplaced entirely.
I have to agree. While I happen to be typing this while at the same time (sort of) IM'ing Andre, and having a conversation with a current colleague about BI, and another about his current project, as well as checking my email, I doubt I am improving the quality of any of these actions by virtue of doing the others at the same (or nearly the same) time.
Let me be clear, I believe the ability to multitask with minimal loss of efficiency is a very important skill. I also believe that multitasking can help improve attention in a monotonous work environment. But I don't believe it ever improves overall efficiency.
Several studies seem to agree with this, as do some notable bloggers. Heck, even Dale Carnegie®, who offers a course on multi-tasking seems to acknowledge that it's a beast that needs to be managed, rather than fed.