Circumstantial evidence is employed in cartel cases in all countries. The better practice is to use circumstantial evidence holistically, giving it cumulative effect, rather than on an item-by-item basis. Complicating the use of circumstantial evidence are provisions in national competition laws that variously define the nature of agreements that are subject to the law. There are two general types of circumstantial evidence: communication evidence and economic evidence. Of the two, communication evidence is considered to be the more important. Economic evidence is almost always ambiguous. It could be consistent with either agreement or independent action. Therefore it requires careful analysis. National treatment of cartels, such as whether they are prosecuted as crimes or as administrative violations, can affect the burden of proof that applies to the cases, and hence the use of circumstantial evidence. It can be difficult to convince courts to accept circumstantial evidence in cartel cases, especially where the potential liability for having violated the anti-cartel provisions of the competition law is high. There are circumstances in countries that are relatively new to anti-cartel enforcement that could affect the extent to which they rely on circumstantial evidence in their cases.