As part of Slate Magazine's Explainer column, Bryan Palmer regularly answers questions about events in the news. Today, with Mark David Chapman's denial of release from prison for John Lennon's murder in 1980, Mr. Palmer asks,"What happens during a parole interview?" His answer gives readers a glimpse into Chapman's parole board hearing, and into the review process of the New York State Board Parole Comissioners. Mr. Chapman is currently serving a 20 years to life sentence and has now been denied parole for the sixth time. 
