For those who already know a great deal about proper research the easiest is just to come out with it. My research approach is based on a narrative, social constructionist, and postfoundational perspective. More generally understandable, although not spot on, would be to convey that I am a qualitative researcher.
Qualitative research would often involve the quest to understand something in more depth. You would definitely want to consider using a researcher if what you need to go on is more than just a hunch of your consultant or facilitator that ran a couple of focus groups.