Is it possible to guarantee advertising results? If you approach advertising as a science instead of an art results are fairly predictable.

The first tangible return from an advertiser’s money, when invested in space, is an
inquiry about the product. That inquiry may be verbal to a clerk over the counter, or it may be by mail, in a written, stamped and posted letter.

But, in either case, it is just an inquiry for the goods, of one sort or another. It is the first
practical evidence that the money spent is earning something tangible in return.

Now it may take two or three times as much conviction in copy to make a consumer
write an inquiry for goods, and post it, as it would have taken to make that same consumer
inquire verbally for the goods advertised, when passing a store that should sell them.