Yesterday, when Lil' Kim was sentenced to a year and a day in prison for lying to a grand jury, it seemed like more proof that rappers just can' t stay out of jail. The conventional wisdom is that for hip-hop stars, there' s a connection between crime and credibility. Every time some rapper poses for a mug shot, there is a chorus of commentators ready to declare that it' s all a publicity stunt. The sentencing of Lil' Kim comes after two months when two rappers faced more serious charges. On June 17 the Philadelphia rapper Cassidy turned himself in to the police, who were looking for him as a suspect in a shooting that killed one man and wounded two others. Less than two weeks later, Cassidy' s second album, 'I' m a Hustla', arrived in stores it makes its debut at No. 5 on this week' s Billboard album chart. And in May, the emerging Atlanta rapper Gucci Mane surrendered in connection with the slaying of a rapper from Macon, Ga., named Pookie Loc the arrest came the same day as the release of his new album, 'Trap House' (Big Cat). Gucci Mane, who was jailed, has said that the killing was self-defense and has suggested that Pookie Loc was connected to his foe and former collaborator Young Jeezy, from the Atlanta group Boyzn' da Hood, which released its thrilling self-rifled debut album on June 21 Jeezy' s highly anticipated solo debut is due on July 26. It' s clear that many rappers find themselves embroiled in violence, but it' s also clear that Radric Davis had plenty to worry about even before he became a Southern sensation named Gucci Mane: he had previously been convicted on cocaine charges. And while a high-profile arrest certainly won' t scare off hip-hop fans, it won' t usually drive them to the record shops, either. Billboard said the arrest gave Gucci Mane a 'big boost on the charts,' but in fact his album made its debut at No. 101. That' s not a very strong showing, especially considering the popularity of Gucci Mane' s breakout hit, 'Icy,' a regional favorite that became a BET favorite, too. The strange troth is that being arrested or going to prison -- even for murder -- isn't likely to have much effect on a rapper' s reputation. When Lit' Kim makes her inevitable return, she' II inevitably have some rhymes about her time inside. But although some fans might admire her for not testifying against her friends (in hip-hop, as elsewhere, loyalty counts for a lot), it is by no means clear that jail will help her career. For a rapper, having your name printed in the police blotter is likely merely to reinforce whatever perceptions fans already have. The Philadelphia rapper Cassidy ______.