Editor's note: Len Ferman is an adjunct professor at University of North Florida and founder of Ferman Innovation LLC. He can be reached at len.ferman@unf.edu.

As a qualitative researcher for over 30 years and a fan of innovation, I’m continually searching for new ways of collecting data for customer insights. Yet over the past decade I’ve migrated to and found great success with a remarkably simple – and borderline old-fashioned – approach to conducting qualitative research: telephone in-depth interviews, which are usually referred to as phone IDIs.

Phone IDIs deliver superior value to clients while also creating a vastly improved respondent experience (RX). In this article, I will attempt to convey the myriad benefits this approach offers for qualitative research.

What are phone IDIs? Phone IDIs quite simply involve holding a phone conversation between a qualitative researcher and an individual respondent. They hearken back to the pre-internet days when the telephone was the primary tool for data collection for most market research and thus may seem antiquated in this digital age. Yet the benefits of phone IDIs are so compelling that my clients nearly always agree to this approach once I present the case for it.

Why? In one sentence: Phone IDIs can be cheaper, faster and better than other forms of qualitative research. This may sound unbelievable given that a survey of qualitative research methods recently indicated that less than 2% of all qualitative research was conducted via phone IDIs. What seems more unbelievable to me as a practitioner is that so little qualitative research is presently using this method. 

Here are the benefits:

Superior sampling. Respondents for phone IDIs can be anywhere in the world. This enables researchers to construct purely random samples, a stalwart characteristic of sound research. Traditional in-person focus groups, in stark contrast, only allow ...