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��Popular Science Monthly
��Putting Speed in Telephone Directories
A SERIES of experiments were re- cently conducted by the New York Telephone Company to ascertam the quickness with which a telephone num-
���Testing the speed of telephone directones. Names in
the arrangement adopted were found in 9.28 seconds as
against 10.36 seconds in the old arrangement
book
��ber could be found with the printed in three different ways.
Dr. J. W. Baird, Director of the psy- chological laboratory at Clarke Uni- versity, Worcester, Massachusetts, was called in to supplement the work of the telephpne men by conducting other tests, using a variety of type arrange- ments. Dr. Baird made nearly four thousand experiments to determine the case and speed with which the average person could find a number on pages of
��the directory set up in various forms. Thirty-two men and women were se- lected as subjects for the tests. Care was taken that these individuals should represent radically different occupations and degrees of experience in the use of the directory
Pages with names begin- ning with the letters I and M and S were selected when tests showed that they va- ried sufficiently in diflficulty to fulfill the purpose of the experiments.
Twelve pages were sub- jected to experiments, an I- page, an M-page, and an S- page, being printed in each of four different page ar- rangements and mounted on cardboard. Each page was placed in a separate "book- let." While the individual tested was looking up a num- ber, the experimenters held stop-watches measuring the time elapsing from the open- ing of the booklet until the subject found and pronounc- ed the number.
To find a telephone nuni- ber in the old telephone di- rectory, the pages of which were set in three-column measure, required an average time of 10.36 seconds. When the subscribers' names were printed in a four-column measure without indentation or leading, the finding time increased to 10.69 seconds. When the lines in the four- column page were set in "staggered" arrangement, i.e., in alternate indentation, the finding- time was reduced to 10.14 seconds. When the type on the four- column page was made slightly higher and, moreover, narrower, taking eleven lines instead of twelve lines to the mch, the finding time was cut to 9.28 seconds. It was this arrangement of the page that was chosen, cutting i .08 seconds from the 10.36 seconds required by the average subscriber to find a number in the old telephone book. This is a gain of more
��than ten per cent.
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