Then, add the total number of Inquiries obtained from your other current Copy, during the same period.

Then divide that total number into the total expenditure for Space used in publication of that Copy.

This will give the average cost per Inquiry, with the kind of Copy you have been regularly using.

Now, compare this with the average cost per Inquiry obtained from the same publications, at the same identical periods, with "Reason-Why" results.

The difference between the cost per Inquiry with the two kinds of Copy will then be a reliable Index to the relative Earning Power of the two competing kinds of copy. Now, use the same "Follow-up" (Booklets and Letters), on all the Inquiries from both Sources.

The percentage of Sales which results from each of the two competitive groups of Inquiries and Follow-up will then determine the relative Profits to the Advertiser from each kind of Copy.

No Test on earth can be more conclusive than this, and none is easier made. And, what such a Test reveals (in difference between Results from two different kinds of Copy) would "stagger" the average Advertiser.

An extensive series of such Tests, carried over a long period of Time, with many differing propositions, has proved a fine consistency in Results.

It proved that the Reason-Why kind of Advertising which sold Washing Machines by mail at one-third the cost of other Copy sold them, would, when applied according to the individual needs of the different articles, also sell Violins, Shoes, or Pianos, in about the same ratio.

Moreover, it has been found that the "something" in Copy which sells these Goods by Mail (at one-half to one-third the cost other Copy sells them), will also sell them through Retailers over the Counter.

That "something" is Selling Force,-Conviction-Salesmanship-saturated into the Copy, with sound Reasons-Why as the foundation.

It is the salient "something" which makes millionaires of some Advertisers in a few years, while other Advertisers, spending the same amount of money for equally good propositions, "go broke."

Now the kind of Advertising which works these Miracles of Success may be the kind you personally like least, quite contrary to your preference in fact.

But, Advertising is not really intended to merely please the Advertiser's fancy. Its first, last and only duty is to Sell Goods for him, and to sell them at less cost than they can be sold without it.

The kind of Advertising which will be found to do this at lowest cost is Reason- Why Salesmanship-on-Paper.

Which is based not on what you like best to read but on what records prove will sell the most Goods to Readers, per dollar of outlay.