English to Italian Marketing Marketing

E' il titolo della guida per l'intervistatore:

GUIDE FOR DEPTH INTERVIEWS

Ho trovato questa definizione di DEPTH INTERVIEW:

Research technique conducted in person in the field (rather than in the researcher's office) by a trained interviewer for the purpose of learning the motivation of consumers in the purchase decision process. In the unstructured home environment, the interviewer interacts with respondents and encourages them (usually in a one-on-one situation) to freely express their opinions, ideas, feelings, thoughts, and attitudes. The objective is to go beyond the superficial and to probe into consumer behavior. Depth interviews, along with focus group interviews, are helpful in the evaluation of consumer reaction to a product or service. See also motivational research.
http://www.answers.com/topic/depth-interview

Sapete a che cosa corrisponde in italiano? Avevo inizialmente pensato ad 'approfondita', ma non credo sia il termine idoneo.
Grazie mille per l'aiuto!