However, serious conceptual and data problems are likely to arise in the estimation and interpretation of tariff equivalents.

In a companion work, the authors compute the AVEs of NTBs for 104 developing and developed countries in which AVEs were estimated at the 6 digit level of the HS (potentially around 5,000 products) using their quantity impact measures and these import demand elasticity estimates.

And until the work of Kee, Nicita and Olarreaga, ad valorem equivalent estimates had never been computed in such a systematic and extensive way.

Thus, they should allow easy retrieval of so called ad valorem equivalents (AVEs), also called implicit tariffs or implicit rates of protection.

The ad valorem equivalents emerged as key, as they determine the level of the base rate to which tiered formula cuts will be applied for those products subject to non ad valorem duties.

Moreover, quantity measures associated with information on import demand elasticities could give price effect estimates and thus allow for the computation of AVEs.

In fact, what Skinner discovered is that, if you put a pigeon in a box like this, and he has to press one of these two keys, and he tries to figure out what the pattern is, and you give him a little reward in the hopper box there if you just randomly assign rewards such that there is no pattern, they will figure out any kind of pattern.