Current Medical Literature: A Quantitative Survey of Articles and Journals
ESTELLE BRODMAN and SEYMOUR I.TAINE
The traditional view of scientific, especially medical, literature is that its volume is so large that it has become impossible to bring it under control by traditional methods. So far as can be ascertained from a reading of the reports on this problem, most previous estimates of the size of the literature have been made either entirely on an a priori basis or by extrapolation from incomplete data. In the latter category, especially, belong estimates based on partial counts of the number of journals published.
Years of experience spent in examining thousands of medical serials convinced us that the use of the journal title as the quantitative unit of the periodical literature was both erroneous and misleading. Since it is the individual article that contains the specific medical information sought, it seemed logical to use this unit as the basis for determining the true size and therefore the indexing load. The results of some trial projects confirmed this subjective impression and also indicated the feasibility of a larger investigation based on the count of periodical articles within the separate journal issues. The present study was undertaken to procure these data; its further aim was to analyze the information obtained, to compare the results with some other studies made on the traditional journal title basis, and, finally, to draw some conclusion regarding the significance of the findings.
The National Library of Medicine makes a planned, regular, and continuing attempt to learn of the existence of and to obtain all the medical serials published throughout the world. As a result of this policy the Library at the end of 1957 held more than 13,000 different substantive and non-substantive serial titles of reasonable currency. For purposes of this study, it was assumed that
ESTELLE BRODMAN and SEYMOUR I.TAINE National Library of Medicine, Washington, D.C.
the number of medical serials, particularly those of a substantive nature, not received at the National Library of Medicine was so small and was probably scattered so widely in terms of subject, language, and country of origin, it would not distort the results obtained. The field of medicine is broadly defined by the Library; it includes the ancillary fields of dentistry, nursing, hospital administration, pharmacy, homeopathy, and osteopathy.
Methods
A modest, part time investigation was set up in the National Library of Medicine. Because of limitations of time, staff, and equipment, only certain data were tabulated and these were analyzed for the most part by hand methods. All current serials coming to the National Library of Medicine for a three-month period (March-May, 1957) were initially divided into two categories: those indexed by the Current List of Medical Literature and those not so indexed. Since the information about the journals in the Current List was already available for previous operational purposes, nothing further was done with this group of titles. Material not indexed by the Current List was next sorted into two further groups: those containing substantive articles (“indexable journals”) and those containing merely news items, abstracts, statistics, and other non-substantive miscellany (“non-indexable journals”).
The number of individual journal issues in each group was counted, after which the non-indexable journals were discarded from this study; the remaining journals, the indexable journals, were analyzed for the following information:
-
Number of articles contained in the journal.
-
Periodicity of the journal and its articles.
-
Language or languages of the journal and its articles.
-
Country of origin of the journal and its articles.
-
Subject or subjects covered by the journal and its articles. (Subject categories used were adapted from the first edition of World Medical Periodicals.)
The information thus obtained was added to equivalent information for the journals and articles indexed in the Current List of Medical Literature to obtain the total picture. The findings were then compared with those of two earlier, somewhat similar studies, that of the Welch Medical Library Indexing Project (1) and that of the second edition of World Medical Periodicals (2) wherever possible.
Findings
A total of 31,423 articles appearing in 2089 journal titles was counted in the three-month period for an annual total of 125,692 articles not indexed in the Current List of Medical Literature. By utilizing the periodicity data and by making an adjustment for the journals issued annually, semiannually, or at irregular intervals which would normally not be received in any single quarter, the annual number of journal titles and issues was estimated to be 2506 and 19,007 respectively. However, because all the current journals, irrespective of their subject fields, which were received in the National Library of Medicine during the three-month period were counted, many items are included which would not be indexed in a general medical index, which, by its subject scope, would be more restrictive than the collecting policy of the Library. For example, while material on bibliography, physics, and chemistry is admitted to the Library collection, it would be excluded from a medical index. If we remove from the count the out-of-scope items, the grand totals of indexable medical materials are reduced by 135 journals, 1165 issues, and 14,436 articles to the figures which appear in Table 1. Throughout the paper, we have used the maximum counts to be certain that we have not erred on the side of under-estimation. Furthermore, no deductions have been made for the considerable quantity of articles in journals in such non-clinical fields as general science, general biology, and psychology which would also not be indexed in a general medical index.
TABLE 1 National Library of Medicine Survey, 1957: Summary table
Substantive serial titles (per year) |
||
Number indexed in Current List of Medical Literature |
1,508 |
|
Number of additional titles found |
2,371 |
|
Total substantive serial titles |
|
3,879 |
Substantive serial issues (per year) |
||
Number indexed in Current List of Medical Literature |
11,434 |
|
Number of additional issues found |
17,843 |
|
Total substantive serial issues |
|
29,277 |
Substantive serial articles (per year) |
||
Number indexed in Current List of Medical Literature |
107,478 |
|
Number of additional articles found |
111,256 |
|
Total substantive serial articles |
|
218,734 |
From these figures it appears that the total indexable medical periodical lit-
erature is just about double the size of the present Current List of Medical Literature, the largest medical index in the world.
PERIODICITY
The frequency with which the material is published is given in Table 2.
TABLE 2 Periodicity of medical literature
|
Periodical Titles |
Periodical Issues |
Periodical Articles |
Periodical Articles per Title |
||
Frequency |
Number |
% |
Number |
% |
||
Weekly |
64 |
1.6 |
3,588 |
18,354 |
8.3 |
270 |
Semimonthly |
75 |
1.9 |
2,040 |
12,336 |
5.9 |
145 |
Monthly |
1220 |
30.4 |
15,240 |
99,107 |
44.8 |
79 |
Bimonthly |
639 |
15.9 |
3,994 |
33,122 |
14.9 |
51 |
Quarterly |
953 |
23.7 |
3,892 |
29,975 |
13.5 |
31 |
Semiannually |
126 |
3.1 |
252 |
2,149 |
1.0 |
17 |
Annually |
369 |
9.2 |
369 |
6,303 |
2.8 |
17 |
Irregularly |
568 |
14.1 |
1,136 |
20,280 |
9.1 |
36 |
Total |
4014 |
99.9 |
30,441 |
221,626 |
100.3 |
— |
It can be seen that in regard to productivity the rank order follows closely the frequency of appearance of the journal. The most frequently appearing type of journal (the weekly) contains more articles per year than the semimonthly, which in turn, contains more articles per year than the monthly, and so on down to the annual publication. This information, often guessed at and now confirmed, is of some interest. For example, the data indicate that whereas the total number of annual, semiannual, and irregularly appearing journals comprise more than a quarter of all journals by title, the indexing workload in terms of articles is actually under 13%. Stated another way, a decidedly misleading impression could be created by the isolated fact that a particular 1063 journals are indexed, since these yield a total of only 28,732 articles.
It is also interesting to note that while overall there is an average of 58.1 articles published per year in each medical journal, the titles now indexed in the Current List yield 71.3 articles per year per title. Also, the average number of articles per journal issue for Current List titles is 9.4 while the same figure for non-Current List journals is only 7.6 articles per issue. This would seem to indicate that Current List journals are more productive than non-Current List titles in numbers of articles they contain; if so, it would mean that indexing of the additional journals would not swell the total in direct proportions to the number added.
GEOGRAPHIC ORIGINS
During the three-month period, journals from 85 countries were received. The results are tabulated in Table 3. However, some of the smaller nations
known to publish at least one medical periodical did not contribute any specimens during the collection period. Quantitatively, both by titles and articles, these omissions should not be significant.
TABLE 3 Geographic distribution of medical literature
|
Periodical Titles |
Periodical Articles |
||||
In Current List |
All periodical titles |
In Current List |
All periodical articles |
|||
Country |
Number |
% |
Number |
% |
||
Algeria |
3 |
6 |
291 |
327 |
||
Argentina |
25 |
55 |
1.52 |
1,892 |
3,784 |
1.7 |
Australia |
6 |
15 |
576 |
896 |
||
Austria |
20 |
45 |
1.24 |
1,130 |
2,222 |
1.0 |
Albania |
0 |
1 |
0 |
56 |
||
Belgium |
36 |
52 |
1.44 |
1,791 |
2,691 |
1.2 |
Brazil |
33 |
90 |
2.49 |
1,127 |
3,335 |
1.5 |
British West Indies |
2 |
2 |
39 |
39 |
||
Bulgaria |
5 |
5 |
387 |
387 |
||
Burma |
1 |
1 |
29 |
29 |
||
Canada |
20 |
55 |
1.38 |
1,494 |
2,662 |
1.2 |
Ceylon |
1 |
2 |
15 |
37 |
||
China |
6 |
14 |
422 |
998 |
||
Chile |
6 |
14 |
270 |
642 |
||
Colombia |
2 |
15 |
40 |
360 |
||
Costa Rica |
1 |
2 |
15 |
47 |
||
Cuba |
11 |
32 |
298 |
918 |
||
Canary Islands |
0 |
1 |
0 |
24 |
||
Cyprus |
1 |
1 |
10 |
10 |
||
Czechoslovakia |
24 |
30 |
1,613 |
1,785 |
||
Denmark |
19 |
41 |
1.14 |
1,076 |
1,824 |
|
Dominican Republic |
1 |
2 |
12 |
92 |
||
Ecuador |
1 |
7 |
16 |
176 |
||
Egypt |
2 |
7 |
134 |
262 |
||
England |
97 |
244 |
6.76 |
8,058 |
16,398 |
7.4 |
Finland |
7 |
16 |
313 |
593 |
||
France |
116 |
297 |
8.23 |
10,997 |
22,485 |
10.2 |
French Guiana |
1 |
1 |
40 |
40 |
||
Formosa |
0 |
1 |
0 |
48 |
||
Germany |
136 |
315 |
8.72 |
12,449 |
25,741 |
11.7 |
Greece |
2 |
11 |
65 |
449 |
||
Guatemala |
1 |
3 |
40 |
96 |
||
Hawaii |
1 |
1 |
36 |
36 |
||
Haiti |
0 |
2 |
0 |
32 |
||
Honduras |
1 |
1 |
20 |
20 |
||
Hungary |
18 |
23 |
1,288 |
1,388 |
||
India |
8 |
42 |
1.16 |
493 |
2,761 |
1.3 |
Indonesia |
1 |
2 |
60 |
68 |
||
Italy |
150 |
345 |
9.55 |
8,668 |
17,192 |
7.8 |
Iran |
1 |
3 |
45 |
181 |
||
Israel |
3 |
9 |
200 |
344 |
||
Ireland (Eire) |
2 |
4 |
144 |
160 |
||
Iraq |
1 |
2 |
20 |
36 |
||
Japan |
22 |
187 |
5.18 |
1,081 |
19,665 |
8.9 |
Jordan |
0 |
1 |
0 |
8 |
||
Kenya |
1 |
1 |
66 |
66 |
By far the largest producer of medical periodical literature, on any basis, is the United States, which furnishes almost one-quarter of all the world’s journals and/or articles. Although in number of journals Italy ranks second to the U.S. with 9.6%, with Germany (8.7%), France (8.2%), and England (6.8%) trailing in that order, on the basis of articles, Germany ranks second with
11.7%, followed in order by France (10.2%), Japan (8.9%), and Italy (7.8%). This qualitative and quantitative variation of the “Big 5” is made especially interesting by the leap into fourth place by Japan which now produces almost 20,000 articles yearly.
Oddly, a national pattern appears to emerge in regard to the average number of articles published in each journal title. As Table 4 indicates, the journals of certain countries are consistently characterized by a high number of articles, others are of a low productivity, and a third group can be described as medium producers:
TABLE 4 Average number of articles per title by country
High |
Medium |
Low |
|||
Japan |
105.2 |
India |
65.7 |
Italy |
49.8 |
U.S.S.R. |
84.8 |
U.S.A. |
62.6 |
Switzerland |
46.5 |
Germany |
81.7 |
Sweden |
61.1 |
Spain |
44.7 |
LANGUAGES
As shown in Table 5, twenty languages are utilized to convey practically all of the world’s medical information in periodicals. The heading “Polylingual”
TABLE 5 Language breakdown of medical literature
|
Periodical Titles |
Periodical Articles |
||||||
In Current List |
All periodical titles |
In Current List |
All periodical articles |
|||||
Language |
Number |
% |
Order |
Number |
% |
Order |
||
Chinese |
4 |
12 |
.3 |
20 |
362 |
938 |
.4 |
15 |
Czechoslovakian |
20 |
25 |
.7 |
14 |
1,470 |
1,690 |
.8 |
12 |
Danish |
5 |
26 |
.7 |
13 |
368 |
924 |
.4 |
15 |
Dutch |
10 |
33 |
.9 |
11 |
996 |
2,000 |
.9 |
11 |
English |
607 |
1,375 |
38.2 |
1 |
45,651 |
82,687 |
37.3 |
1 |
Finnish |
3 |
10 |
.3 |
21 |
134 |
402 |
.2 |
17 |
French |
152 |
384 |
10.7 |
3 |
13,358 |
28,254 |
10.9 |
3 |
German |
155 |
394 |
10.9 |
2 |
13,681 |
28,729 |
13.0 |
2 |
Hungarian |
14 |
16 |
.4 |
18 |
1,037 |
1,137 |
.5 |
14 |
Italian |
151 |
352 |
9.8 |
5 |
8,699 |
16,699 |
7.5 |
5 |
Japanese |
1 |
128 |
3.5 |
7 |
108 |
17,232 |
7.8 |
4 |
Norwegian |
1 |
13 |
.4 |
19 |
144 |
536 |
.2 |
17 |
Polish |
31 |
39 |
1.1 |
10 |
1,702 |
2,302 |
1.0 |
10 |
Polylingual |
110 |
132 |
3.7 |
6 |
5,900 |
7,316 |
3.3 |
7 |
Portuguese |
42 |
121 |
3.4 |
8 |
1,584 |
4,356 |
1.5 |
9 |
Rumanian |
7 |
19 |
.5 |
17 |
224 |
1,804 |
.8 |
12 |
Russian |
56 |
75 |
2.1 |
9 |
5,290 |
6,930 |
3.1 |
8 |
Serbo-Croatian |
14 |
24 |
.7 |
15 |
697 |
1,173 |
.5 |
14 |
Spanish |
109 |
358 |
9.9 |
4 |
5,190 |
13,806 |
6.2 |
6 |
Swedish |
2 |
22 |
.6 |
16 |
46 |
770 |
.3 |
16 |
Turkish |
3 |
10 |
.3 |
22 |
132 |
456 |
.2 |
17 |
Other |
11 |
28 |
.8 |
12 |
705 |
1,485 |
.7 |
13 |
Total |
1508 |
3597 |
99.9 |
|
107,478 |
221,626 |
99.5 |
|
refers to the journals which include articles written in more than a single language; “Other” includes all material in a single language other than the twenty already listed for which fewer than 10 journal titles were located.
Table 5 shows that English is by far the most common language (over 37% of the articles). Here again, as in the geographic breakdown, a similarly intriguing variation between journal and article counts emerges. In regard to journals, German ranks second with 10.9%, followed very closely by French (10.7%); Spanish and Italian run a close fourth and fifth, with 9.9% and 9.8% respectively. On the article basis, German is again second to English with 13%, just slightly ahead of French at 12.9%. Fourth place is, however, usurped by Japanese with 7.8%, and Italian is in fifth with 7.5%. Russian trails far behind in eighth place with a little over 3% of the total. Some quick arithmetic reveals the interesting fact that about 85% of the medical periodical literature is written in but six languages.
SUBJECTS
Any attempt to subdivide the field of medicine into its component parts is, at best, a frustrating procedure and rarely, if ever, does it produce a result that is completely satisfying. Much of the difficulty, apart from the ever-broadening scope of medicine, may be attributed to the inherent characteristics of the various related subject fields and specialties which resist a clean, sharp, and exclusive compartmentalization. For example, the subject field under which the greatest quantity of medical periodical literature falls is known as “general medicine.” Actually, the specific articles which appear within these general medical journals can be distributed without strain among the different smaller subdivisions provided in the classification. Unfortunately, because of time limitations, the present study had to change its basis and restrict the subject breakdown of the collected material to the journal title and not, as in other cases, to the individual article itself.
Despite these solid reservations, the figures in Table 6 are still of interest and value, although more limited than might be hoped. Its greatest usefulness will probably be found in the data for the more easily circumscribed fields such as dermatology and ophthalmology.
Comparison with other studies
The findings of this investigation can be profitably compared with those of the Welch Medical Library Indexing Project and the second edition of the World Medical Periodicals. Unfortunately the latter work appeared just at the conclusion of the National Library of Medicine survey; it is to be regretted that
TABLE 6 Subject breakdown of medical literature
|
Periodical Titles |
Periodical Articles |
||||
In Current List |
All periodical titles |
In Current List |
All periodical articles |
|||
Subject |
Number |
% |
Number |
% |
||
Alcoholism |
2 |
12 |
55 |
227 |
||
Allergy |
6 |
7 |
273 |
493 |
||
Anatomy (incl. embryology) |
33 |
48 |
1.2 |
1,231 |
2,303 |
1.0 |
Anesthesiology |
12 |
17 |
647 |
1,363 |
||
Anthropology |
2 |
14 |
66 |
470 |
||
Antibiotics |
8 |
11 |
635 |
687 |
||
Aviation Medicine |
8 |
8 |
223 |
223 |
||
Athletics |
0 |
10 |
0 |
524 |
||
Bibliography |
1 |
20 |
52 |
596 |
||
Biochemistry |
31 |
37 |
1.1 |
3,099 |
3,491 |
1.5 |
Biology, general |
21 |
54 |
1.4 |
1,194 |
2,778 |
1.1 |
Beauty culture |
0 |
2 |
0 |
56 |
||
Cancer |
26 |
34 |
1.0 |
1,603 |
1,815 |
|
Cardiovascular system |
29 |
43 |
1.1 |
1,426 |
2,614 |
1.1 |
Chemistry |
1 |
37 |
1.0 |
12 |
9,260 |
4.1 |
Chiropody |
1 |
9 |
60 |
268 |
||
Chiropractic |
0 |
5 |
0 |
248 |
||
Chronic disease |
1 |
1 |
108 |
108 |
||
Criminology |
0 |
9 |
0 |
260 |
||
Civil Defense |
0 |
1 |
0 |
64 |
||
Dentistry |
4 |
180 |
4.5 |
456 |
8,296 |
3.4 |
Dermatology |
29 |
50 |
1.3 |
2,117 |
3,625 |
1.5 |
Diabetes |
1 |
7 |
51 |
187 |
||
Education |
0 |
2 |
0 |
92 |
||
Endocrinology |
17 |
21 |
1,192 |
1,396 |
||
Engineering |
0 |
1 |
0 |
72 |
||
Enzymology |
5 |
5 |
114 |
114 |
||
Experimental medicine |
88 |
101 |
2.5 |
5,755 |
6,383 |
2.6 |
Food technology |
1 |
10 |
49 |
669 |
||
Gastroenterology |
18 |
29 |
1,167 |
2,779 |
1.1 |
|
General medicine |
332 |
817 |
20.4 |
33,143 |
60,147 |
24.5 |
Genito-urinary system |
19 |
27 |
1,103 |
1,743 |
||
Geriatrics |
5 |
11 |
289 |
517 |
||
Gynecology and obstetrics |
48 |
76 |
1.9 |
3,393 |
5,369 |
2.2 |
Hematology |
17 |
24 |
786 |
1,322 |
||
Heredity and genetics |
13 |
22 |
321 |
649 |
||
History of medicine |
8 |
24 |
126 |
566 |
||
Homeopathy |
2 |
22 |
|
208 |
972 |
|
Hospitals |
8 |
47 |
1.2 |
957 |
2,949 |
1.2 |
Hydrology and climatology |
1 |
14 |
24 |
764 |
||
Hygiene and public health |
42 |
162 |
4.1 |
2,207 |
5,799 |
2.4 |
Hypnosis |
0 |
2 |
0 |
44 |
||
Illustration, etc. |
4 |
5 |
115 |
143 |
||
Immunology |
11 |
11 |
421 |
421 |
||
Industrial hygiene |
20 |
45 |
1.1 |
988 |
2,224 |
1.0 |
Infectious diseases |
24 |
31 |
1,426 |
1,826 |
|
Periodical Titles |
Periodical Articles |
||||
In Current List |
All periodical titles |
In Current List |
All periodical articles |
|||
Subject |
Number |
% |
Number |
% |
||
Internal medicine |
14 |
21 |
1,091 |
1,631 |
||
Jurisprudence, medical |
8 |
21 |
253 |
753 |
||
Leprosy |
4 |
8 |
83 |
195 |
||
Malaria |
3 |
5 |
80 |
140 |
||
Maternity and child welfare |
0 |
14 |
0 |
532 |
||
Medical profession |
3 |
13 |
177 |
953 |
||
Medical technology |
10 |
19 |
435 |
755 |
||
Medicine and religion |
0 |
8 |
|
0 |
360 |
|
Microbiology |
42 |
54 |
1.4 |
2,728 |
3,360 |
1.4 |
Microscopy |
4 |
7 |
133 |
313 |
||
Military and naval medicine |
37 |
44 |
1.1 |
1,491 |
1,679 |
|
Mycology |
1 |
2 |
2 |
150 |
||
Naturopathy |
0 |
6 |
0 |
468 |
||
Neurology |
50 |
71 |
1.8 |
2,625 |
3,433 |
1.4 |
Neurosurgery |
11 |
13 |
454 |
642 |
||
Nursing |
5 |
45 |
1.1 |
531 |
2,483 |
1.0 |
Nutrition |
16 |
32 |
1,018 |
1,630 |
||
Occupational therapy |
7 |
25 |
348 |
920 |
||
Ophthalmology |
40 |
76 |
1.9 |
2,306 |
4,302 |
1.8 |
Orthopedics |
18 |
44 |
1.1 |
1,022 |
2,194 |
|
Osteopathy |
1 |
18 |
144 |
784 |
||
Otorhinolaryngology |
35 |
60 |
1.5 |
2,146 |
3,250 |
1.3 |
Parasitology |
16 |
23 |
748 |
1,288 |
||
Pathology |
36 |
46 |
1.2 |
2,537 |
3,257 |
1.3 |
Pediatrics |
59 |
92 |
2.3 |
3,778 |
5,694 |
2.3 |
Pharmacology |
34 |
39 |
1.0 |
2,462 |
2,782 |
1.1 |
Pharmacy |
15 |
113 |
2.8 |
767 |
4,487 |
1.8 |
Philosophy |
0 |
2 |
0 |
76 |
||
Physics |
12 |
26 |
1,328 |
2,956 |
1.2 |
|
Physiology |
44 |
48 |
1.2 |
3,337 |
3,561 |
1.5 |
Physiotherapy |
13 |
33 |
556 |
1,508 |
||
Plastic surgery |
3 |
6 |
190 |
382 |
||
Population |
0 |
3 |
0 |
180 |
||
Psychiatry |
63 |
103 |
2.6 |
3,086 |
3,974 |
1.6 |
Psychoanalysis |
8 |
15 |
292 |
468 |
||
Psychology |
27 |
73 |
1.8 |
1,325 |
3,581 |
1.5 |
Plants |
0 |
7 |
0 |
476 |
||
Radiodiagnosis, etc. |
29 |
48 |
1.2 |
2,452 |
3,300 |
1.3 |
Red Cross |
0 |
6 |
0 |
208 |
||
Rheumatism |
13 |
20 |
535 |
659 |
||
Science, general |
10 |
76 |
1.9 |
1,865 |
8,713 |
3.6 |
Serology |
4 |
4 |
169 |
169 |
||
Sex |
0 |
3 |
0 |
112 |
||
Social medicine |
6 |
16 |
280 |
688 |
||
Sociology |
0 |
13 |
0 |
920 |
||
Speech disorders |
2 |
5 |
74 |
162 |
||
Statistics |
0 |
2 |
0 |
264 |
||
Surgery |
106 |
193 |
4.8 |
8,227 |
12,903 |
5.3 |
time and staff were not available to do a thorough comparison of the two lists, especially in the language, country, and periodicity areas. It is to be hoped that further work can be done on this in the future. The Welch Library Indexing Project, sponsored by the predecessors of the present National Library of Medicine, carried on its work from 1948 to 1953. Among its other activities, the Project also undertook to do a comprehensive survey of the world’s medical serials.
Table 7 gives comparative figures of the total number of journals studied by the three groups.
TABLE 7 Comparative counts of medical periodicals
Welch Medical Library Indexing Project Survey |
4454 |
World Medical Periodicals |
4360a |
National Library of Medicine Survey |
3879 |
a Current titles only. |
The differences between the National Library of Medicine figure and those of the other two are not as significant as would appear at first glance. The Welch Medical Library figures are higher on account of differences in definition of current substantive periodicals. Actually, an adjustment on the basis of like criteria would probably effect an extremely close alignment; this is not surprising in view of the wide use made by the Indexing Project of the serial holdings of the National Library of Medicine.
The apparent discrepancy between the National Library of Medicine and World Medical Periodicals is almost entirely due to the coverage from two specific geographic areas in the National Library of Medicine. The National Library of Medicine is now overcoming a lag in the acquisition of materials from Latin-America and Japan occasioned by an earlier policy decision to collect selectively from these regions. Some 90% of the differential between the two
totals appears to consist of Latin-American journals whose average output of articles is generally acknowledged to be quite low.
Tables 8 to 10 are comparisons of the results in terms of journal titles of the National Library of Medicine and of the Welch Medical Library Indexing Project. In spite of the time interval between the two investigations, there is a high degree of correlation; 0.905 for periodicity and 0.947 for languages, for example.
TABLE 8 Comparison of periodicity of medical journals
|
National Library of Medicine Survey |
Welch Medical Library Indexing Project Survey |
||
Frequency |
Number |
% |
Number |
% |
Weekly |
64 |
1.6 |
93 |
2.0 |
Semimonthly |
75 |
1.9 |
95 |
2.0 |
Monthly |
1220 |
30.4 |
1518 |
34.0 |
Bimonthly |
639 |
15.9 |
603 |
14.0 |
Quarterly |
953 |
23.7 |
868 |
19.0 |
Semiannually |
126 |
3.1 |
73 |
1.6 |
Annually |
369 |
9.2 |
385 |
9.0 |
Irregularly |
568 |
14.1 |
822 |
18.4 |
Total |
4014 |
99.9 |
4454 |
100.0 |
TABLE 9 Comparison of geographic origin of medical journals
|
National Library of Medicine Survey |
Welch Medical Library Indexing Project Survey |
||
Geographic Division |
Number |
% |
Number |
% |
Europe |
2015 |
55.9 |
2012 |
47.2 |
North America |
944 |
26.2 |
1382 |
31.0 |
Asia |
295 |
8.2 |
336 |
7.5 |
Latin America |
283 |
7.9 |
523 |
11.7 |
Africa |
38 |
1.1 |
45 |
1.0 |
Australasia |
25 |
.7 |
39 |
.9 |
Other |
0 |
0 |
27 |
.6 |
Total |
3597 |
100.0 |
4454 |
99.9 |
TABLE 10 Comparison of languages of medical journals
|
National Library of Medicine Survey |
Welch Medical Library Indexing Project Survey |
||
Language |
Number |
% |
Number |
% |
English |
1375 |
38.2 |
2061 |
41.2 |
German |
394 |
10.9 |
545 |
10.9 |
French |
385 |
10.7 |
600 |
12.0 |
Spanish |
358 |
9.9 |
608 |
12.1 |
Italian |
352 |
9.8 |
348 |
6.9 |
Polylingual |
132 |
3.7 |
0 |
0 |
Japanese |
128 |
3.5 |
187 |
3.7 |
Portuguese |
121 |
3.4 |
196 |
3.9 |
Russian |
75 |
2.1 |
85 |
1.7 |
Polish |
39 |
1.1 |
34 |
.7 |
Dutch |
33 |
.9 |
49 |
1.0 |
Danish |
26 |
.7 |
39 |
.8 |
Czechoslovakian |
25 |
.7 |
38 |
.8 |
Serbo-Croatian |
24 |
.7 |
22 |
.4 |
Swedish |
22 |
.6 |
46 |
.9 |
Rumanian |
19 |
.5 |
1 |
0 |
TABLE 10 Comparison of languages of medical journals
|
National Library of Medicine Survey |
Welch Medical Library Indexing Project Survey |
||
Language |
Number |
% |
Number |
% |
Hungarian |
16 |
.4 |
26 |
.5 |
Norwegian |
13 |
.4 |
14 |
.3 |
Chinese |
12 |
.3 |
1 |
0 |
Finnish |
10 |
.3 |
17 |
.3 |
Turkish |
10 |
.3 |
21 |
.4 |
Less than 10 |
28 |
.8 |
70 |
1.4 |
Total |
3597 |
100.0 |
5008 |
99.9 |
Summary
An investigation was undertaken to determine the approximate size and composition of present-day medical periodical literature by employing as the basic counting unit not the journal title, so frequently used in such investigations, but the journal article. Our object was to do away with the difficulty encountered in most previous studies, where certain assumptions had to be made about the relationship between journal titles and journal articles.
Data were collected on the number of journal titles and journal articles published in 1957, their periodicity and country of origin, the languages in which they were published, and their subject breakdown. Analysis of these data showed a direct linear relationship between the number of issues of a journal published (its periodicity) and the number of articles in it. On the other hand, there appears to be a true variation in the average number of articles published per journal title on the basis of the geographical origin of the journal, and linguistically, substantial deviations are encountered between journal title counts and article counts.
It was also possible to analyze the data of the medical periodical literature for the probable magnitude of what would logically be indexed in a general medical index. This turns out to be about 220,000 articles per year, or approximately twice the number already listed in the Current List of Medical Literature, the largest general medical index we now possess.
We believe the statistics presented here can be used meaningfully in additional ways, only a few of which are mentioned in this paper. It is to be hoped that further work can be undertaken in the future.
REFERENCES
1. WILLIAMINA A.HIMWICH and others. Survey of world medical serials and coverage by indexing and abstracting service, Welch Medical Library indexing project sponsored by the Armed Forces Medical Library. Baltimore, 1954.
2. LESLIE T.MORTON, comp. World medical periodicals, 2nd edition, World Medical Assoc., Geneva, 1957.