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1) Every parole hearing is on a case by case basis, based on subjective factors and the discretion of the parole board members. There is no specific "formula" for percentage of chance.
2) However, one can get a "general feeling" of his chances by the severity of his conviction as the parole board sees HERE.
3) As you can see, assault against a peace officer is labeled "F1 - HIGHEST" severity. This means, I am sorry to say, chances are slim that he would receive parole the first time around.
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