Structured Interview - 'Verbal Questionnaire' Participant responds verbally to a set list of questions. The researcher is not allowed allowed to add more questions or 'prope.'
Unstructured Interview - The interviewer has a general topic nut the interviewee has freedom to dictate conversation and talk freely about the topic. Interviewer creates questions depending on respondants' answers.
Semi-structured Interviews - There is a predetermined topic but may interviewer may not have listed questions but certain topics they have to cover.