Increasing numbers of countries require mobile telephone networks to offer mobile number portability (MNP). MNP allows customers who wish to switch mobile operator to keep their mobile numbers, avoiding the costs of switching to new numbers. Ex ante assessments suggest that MNP should reduce...

When assessing the likely net impact of regulation, many jurisdictions test for specific effects on areas of concern, such as small businesses or the environment, as well as for more generalised costs and benefits. This paper considers how best to design a negative-clearance test for the...