IncX-ionary defines Credible Artist as:
someone who knows what he is talking about, has beliefs to back up the material he/she releases... has the intelligence to critic his own work and therefore improve it on the next albums. and finally, is realistic enough to know his real strengths and weaknesses and never attempt to sing in C#m when he knows he can't hit that key.
and oh... doesn't give a sh*t about the underground nor the mainstream... he knows who his audiences are, and lets the management decide on how to label them.
example of credible artists:
Trent Reznor, Ian Mckaye (not sure if i spelled the name right), Les Claypool, Paul Mcartney (i dont like him though, but you gotta have respect for that guy), Pat Metheny (he knows his jazz. im not a fan though). i cant come up with pinoy counterparts.