In a civil case, a plaintiff has the burden of presenting relevant and convincing evidence by a “preponderance of evidence”, in other words, the plaintiff is supposed to prove that something is more likely than not.  This is generally understood as establishing a threshold degree of certainty just above 50% for a ruling in favor of the party with the burden of proof. In contrast, in criminal cases, the burden of proving the plaintiff’s guilt must be established beyond a reasonable doubt.