Many advertisers adopt the policy of repeating full-page advertisements
at long intervals instead of advertising in a small way continually.
Laboratory tests have shown, on the contrary, that a quarter-page
advertisement appearing in four successive issues of a newspaper is
fifty per cent more effective than a full-page advertisement appearing
only once. It does not follow, however, that an eighth-page
advertisement repeated eight times is correspondingly more effective;
for below a certain relative size the value of an advertisement
decreases much more rapidly than the cost. There are, of course,
modifying conditions, such as special sales of department stores, where
occasional displays and announcements make it desirable to use either
full pages, or even double pages, but the great bulk of advertising is
not of this character.

[Sidenote: _Ratio of Size to Value_]

Every year in the United States alone six hundred millions of dollars
are expended in advertising the sale of commodities, and for the most
part expended in a haphazard, experimental and unscientific way. The
investment of this vast sum with risk of perhaps total loss, or even
possible injury, through the faulty construction or improper placing of
advertisements should stimulate the interest of every advertiser in the
work that psychologists have done and are doing toward the accumulation
of a body of exact knowledge on this subject.

[Sidenote: _Risks in Advertising_]