At the actual interview, one person can be in control by simply making sure the recorder is taping and picking up the voices. The obvious flip side is that audio does not allow for any visuals, but does allow for more creativity by the student in their actual presentation. Like CNN's COLD WAR, video footage enables the viewer to see a degree of the story just by observing the interviewee. Video requires an extra person, in addition to the interviewer, to be present. Students will need to be aware of basic camera operation.
Video also requires slightly more detailed preparation, however the rewards can be worth it.
You may decide to ask two to three people to come in to your class and have students ask questions. The students can call their subjects and have them meet at the school. Or, the students can go out on location to conduct the interview. Then have the interviewee and interviewer sign and date the release. The final product consists of a paper about the interview and a class presentation on their findings.