The following figures are from an actual test of a direct-by-mail campaign to secure subscriptions to a publication. The prospects were all bankers. No follow-ups were used. The advertiser established as his minimum twenty orders a thousand; and if a letter did not "pull" to that extent, he saved himself the expense of sending it to the entire list. The percent age returns from the tests and from the actual mail ings were found to be nearly the same.' Note: Where the same letter appears with different ex ponents under "material mailed" it indicates that on the test mailing, results were kept separately for the same material mailed to two small groups.
11. Tests of follow-up series.—A trial campaign to establish the proper number of letters in a series of follow-ups may require so much time as to be impos sible. The advertiser may be compelled to decide from judgment rather than from experiment. He knows that in the first part of the series the succession of appeals will operate to his favor but that a "dimin ishing return" will operate against him somewhere in the latter part of the series. Just where in the series will one additional letter be unprofitable? The re mainder of this chapter is devoted to precisely this question.
Following is a record of seventeen follow-up letters which were sent at weekly intervals to 2,300 dealers in twelve eastern states to induce them to carry the Moneybak Taffeta Selvage Silks, made by the New York Silk Manufacturing Company. The entire campaign cost $1,554.
Eleven of these letters, one to eleven inclusive, were used on another list of 4,800 dealers in the remaining states of the country, with the results shown in the following table: 12. Taking the average of a inter esting record shows the returns from a series of six letters sent out by an advertising specialist who planned to make a six months' campaign pay on the basis of the net profit from new accounts.
If this advertiser had stopped at the end of the third letter, as some might think lie would have been justi fied in doing, he would have nothing but a new loss of $212 to show for his efforts. By continuing thruout the series, he was able to obtain new accounts on which he received a net profit of about ten times the cost of the campaign.