A study involved video observation of group dynamics during student discussions over the course of tutorials in one academic year.All students who participated in the discussions had signed consent forms, agreeing to be videoed.Subsequently, one student dropped out of the course and decided that he also wanted to withdraw from the study. He asked for his data to be destroyed. The researcher was very reluctant to do this, as destroying the video recordings would mean that she lost data on all the other students who had been involved in those discussions. How might you avoid this ethical dilemma in the future?