Since penalties are only one of many administrative and procedural aspects of a tax system, it is difficult to conclude whether a particular penalty is fair or not without considering the other aspects of the tax system. Nonetheless, OECD member countries agree that the following conclusions can be drawn regardless of the other aspects of the tax system in place in a particular country. First, imposition of a sizable “no-fault” penalty based on the mere existence of an understatement of a certain amount would be unduly harsh when it is attributable to good faith error rather than negligence or an actual intent to avoid tax. Second, it would be unfair to impose sizable penalties on taxpayers that made a reasonable effort in good faith to set the terms of their transactions with associated enterprises in a manner consistent with the arm’s length principle. In particular, it would be inappropriate to impose a transfer pricing penalty on a taxpayer for failing to consider data to which it did not have access, or for failure to apply a transfer pricing method that would have required data that was not available to the taxpayer. Tax administrations are encouraged to take these observations into account in the implementation of their penalty provisions ...