On one level I don't believe I have the impostor syndrome because I understand how little I really know in the grand scale of theory, two advanced degrees and 40 years of management experience aside. Also I'm open and honest about my limitations. For example, my expertise is in organizational studies. So if I were to be in a meeting and detailed questions were to arise about accounting rules and banking relations, I would defer to those better qualified and more knowledgeable in those areas.
On another level, yes, I have momentarily felt like an impostor. For example, when I was on adjunct faculty (evening division) at a college and lecturing on principles of management, I could sense that there were some undergrads in the classroom who ASSUMED that because I had advanced degrees that I must know all the literature, theories, and have all the answers. Especially during the first class I'd get that uneasy impostor feeling. To relieve that unease, I'd tell the students flat out that I didn't have all the answers, that we were a learning community, and as such, we'd be learning from one another and together. Once I could sense that they then saw me as a mortal human being rather than the experts' expert, my feeling of being something less than their initial expectation--that is, an impostor--would quickly fade away thankfully. To make it dissipate, my approach was to frankly treat it as a vulnerability, put it out on the table and deal with it. It always worked well.
Let me give you this insight too: PhD programs aimed at research and teaching require the student to be very highly specialized, and when a dissertation is written, it's in an incredibly narrow area of inquiry, but also very deeply and thoroughly researched. Those doing practitioner doctorates, DBA, DMA, etc. focus much more on the broad scope of knowledge in the discipline. Even a concentration is still very broad. So here's an exaggeration, but it will make my point. The PhD (who is a practicing scholar) ends up knowing everything there is to know about virtually nothing, while the DBA, DMA etc. (who are scholarly practitioners) end up knowing a little bit about everything.
An exaggeration to be sure, but there is some truth to it. Either way, be it a lack of breadth OR depth of knowledge, either kind of doctoral "expert" can often feel uncomfortable in certain situations, which can naturally lead to being momentarily haunted by the the impostor syndrome. That's why it's useful for practicing scholars and scholarly practitioners to collaborate and consult with one another--they help fill in the knowledge gaps in each other's training.
For those who are too egotistical or insecure to openly share the vulnerability of the limits of their knowledge, they probably develop permanent impostor syndrome in my opinion, which is sad. On the other hand, those who have developed an approach to deal with it will still be momentarily confronted by the syndrome to be sure, but will resolve it openly and effectively in the circumstances and move on.
Topic: Impostor Syndrome: Anyone else have it?