---------- Forwarded message ----------
Date: Fri, 12 Jul 1996 16:47:21 GMT+2
From: Heinrich C. Kuhn <hck@IPP-GARCHING.MPG.DE>
Subject: Caveats when using bibliographical DBs

In my response ((Thu, 11 Jul 1996 11:39:47 -0400) to Albert
Henderson's kind reply to a request for further information
by me) I expressed some doubts as to the reliability of statistical
information drawn from bibliographical databases as a basis for
conclusions on the number of publications of a certain type in a
certain period of time. Yesterday I used data from INSPEC and
INSPHYS. Today I tried the more or less same thing in MEDLINE
(clinical medicine etc.) and what I found is far more apt to
fundament my pledge for caution than what I mailed yesterday.

The search was for publication-type=monograph and *entry* years
(by combining information from the entry-month-field). Here are
the numbers:

YEAR           MONOGRAPHS
1966-1974            0
1975                 0
1976             11794
1977              5135
1978              3055
1979              1875
1980               916
1981                62
1982                 0
1983-1995            0

It is obvious: An interpretion that runs like this: "Publishing
of monographs in clinical medicine and related fields was in-
existant from 1966 to 1975. It started on a very high level in
1976. Over the years 1977 to 1981 there was a very sharp decline.
>>From 1982 to 1995 no monographs were published.": thus an inter-
pretation would be utterly absurd. These numbers are about
indexing, and probably *about indexing only*!

Thus: Be cautious: Bibliographical databases are valuable tools
for quite a number of things, but they do not necessarily provide
reliable data for conclusions about the development of the numbers
of a certain type of publications in a certain field!

Regards

Heinrich C. Kuhn

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