CONCENTRATION OF USE 101

lengthened to a full year. Over the longer period, the frequent
borrowers from the library have much more opportunity to
“pile up,” and they do. In so far as can be determined by these
data, only 5 percent of the total annual borrowers account
for about 40 percent of the circulation and about 20 percent
for 75 percent. Thus, there is a heavy concentration of library
use by a small group of frequent borrowers.*

One consequence of such concentration is that this group
largely determines the character of the public library’s entire
circulation. Another is that the direct impact of the public
library is for the most part limited to a much smaller group
than registration or even the record of number of borrowers
would suggest, for a few borrowers take out many books with
unusual frequency.

REGISTRATION, CIRCULATION, AND CONCENTRATION In fact,
registration data are not reliable indicators of the extent to
which the library “reaches” the community. This can be
demonstrated by a special analysis, carried out by means of
a punch-card system of recording circulation, for the Free
Public Library of Montclair, New Jersey.” The Montclair
Library is not a “typical” library by the usual criteria; it
ranks especially well by the standards of service of the Ameri-
can Library Association. However, in terms of concentration
of use it may well be representative of libraries in this coun-
try.

In order to eliminate some of the “dead” cards from its
files, the Montclair library changed its registration system
during the period of this analysis. The change is reflected in

In fact, concentration of library use is greater than that for any of the mass
media (Chart X). Thus, the correlation between size and concentration of
audiences is maintained.

*We are grateful to Miss Marguerite Gates, technical process specialist, and
Miss Margery Quigley, librarian of the Montclair Library, for their kind
interest and co-operation in this analysis.