MARBLEHEAD – Directed study, a form of study hall and a subject of discussion at last week’s School Committee meeting, was also discussed at Tuesday afternoon’s Marblehead High principal interviews.School Committee Chairman Dick Nohelty and committee member Jonathan Lederman questioned the educational value of high school students spending 16 percent of their time in study halls instead of going to a class. “They (study halls) don’t do kids any good,” Nohelty said.Superintendent of Schools Paul Dulac said directed study puts 20-25 students in a classroom with a teacher who can help them learn, unlike the 250-student study halls of 30 years ago. Committee member Patricia Blackmer said students do homework there.High school junior Josh Chmara, who led the student interviews of the possible principals, told Ken Weinstein, secular studies administrator of the Maimonides School, a private school in Brookline, “Some kids have three study halls a day,” and asked his thoughts on scheduling to avoid this.Weinstein reviewed the complexities of scheduling for the students. “You have to consider what kind of course can handle more than 25 students,” he said, adding that the school budget is also a factor.Swampscott High Assistant Principal Bryan Menegoni suggested independent study as a way that Swampscott High gets around class scheduling difficulties. “It’s not the same as a class but students get to follow their interests,” he said.Marblehead High Assistant Principal Kristina Kyles, who prepared the school budget this year, asked the School Committee to find a way to fund an additional social studies teacher and said teachers are needed in other subjects as well.