Literature growth and decay: an activation analysis résumé

Literature growth and decay: an activation analysis résumé Most chemists read a technical paper or two, and some occasionally write one. All readers are aware of how the scientific literature seems to be ever expanding; those under the age of 35 think that once the literature was more manageable; those over the age of 45 know it was so! Are these memories real? If the journal literature really was smaller in the past, how and when did it grow? And more importantly, if it grows, does it decay? A number of authors have addressed the general subject of literature proliferation, and some general observations (laws?) have resulted. Derek de Soila Price probably is the best known of such writers, and his two books "Little Science, Big Science" (1) and "Science Since Babylon" (2) are delightful reading for anyone interested in the growth of science. And lest anyone think scientometrics is not of real practical dol-

Figure 1 . Growth of publications on a c tivation analysis

lars and sense value, he might cast his eyes over recent reports which suggest that science citations be used as a primary indicator of achievement for a scientific career (3). (This part of the story we will touch briefly on later.) In a recent book Menard (4) has expanded on some of the themes of de Solla Price and applied his approach to several disciplines—primarily geology. Menard discusses the growth of subfields and pays particular attention to how such specialties follow a pattern of rapid growth, maturity, and finally stability, a pattern similar in many ways to that of human life. Coming closer to home, in 1975 Brooks and Smythe (5) published a paper, "The Progress of Analytical Chemistry 1910-1970", which was really more of a study of the progress of the literature of the subject. One of us (T. Braun) in commenting on this paper summarized some of the basic background information relative to growth in the literature of science (6). "The growth of the number of scientific publications is exponential, as has been shown both for all science (1, 7, 8) and for several individual fields. It is usual to characterize further the exponential increase by a growth rate that can be compared with the growth rate of chemistry in general or with that of some other fields (4). A very convenient, simple way to compare various rates of exponential growth is by means of the doubling time, the length of time required for the literature to double in size, when growing at constant rate. The problems in attempting to assess the total volume of analytical literature are so great and diverse as to cast doubts on the value of any such estimate. It seems that it is more reliable to look at and compare the rates of growth of the various techniques." Since we are participants in a sub-

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field of analytical chemistry that essentially did not exist 35 years ago, it seemed interesting and perhaps educational to examine the literature of activation analysis and to look at some of the techniques within it. One of us (W. S. Lyon) had earlier reported in ANALYTICAL C H E M I S T R Y on some aspects of the literature of activation analysis as exemplified in three international meetings (9). If the reader has progressed this far, most of his troubles are over since the rest of this report consists mainly of graphs we have constructed from numerical data. Only one definition is needed to understand these data; this is the doubling time (Td). Radiochemists should feel right at home with it, since the doubling time (as previously defined) is the time required for a given quantity (number of papers or people, for example) to double in size when growing at a constant rate. When numerical data are plotted as the abscissa on a log scale as a function of time on the linear ordinate, the resulting plot resembles a decay curve reflected upward 90°. The data presented below come mainly from the NBS bibliographies of activation analysis (10), except as otherwise noted. Our data describe growth primarily of the years up to 1970. G r o w t h of Publications on Activation Analysis

Figure 1 shows the growth of total publications in activation analysis as a function of time. (See also ref. 10.) The doubling time (Td) of three years remains constant over four decades (13 doubling periods). Like the population explosion, the growth of papers suddenly became obvious about 10 years ago. It is interesting to look at several subfields of activation analysis: Charged particle activation (Figure 2) rose from virtual obscurity in the 1950's and now follows closely the overall activation analysis doubling time. Forensic activation analysis also

Τ. Braun

Report

Institute of Inorganic and Analytical Chemistry L. Eötvös University P.O.B. 123 H-1443 Budapest, Hungary

W. S. Lyon Analytical Chemistry Division Oak Ridge National Laboratory Oak Ridge, Tenn. 37830

E. Bujdosó Research, Engineering and Prime Contracting Centre Hungarian Aluminum Corp. P.O.B. 128 H-1389 Budapest, Hungary

graph paper. These two subfields— forensic and solid-state detectors—are shown together both for contrast and for prognostication. We predict t h a t as solid-state detectors begin to be seriously applied in forensic activation analysis, Td for the latter will sharply decrease.

Fading Neutron Generator

Figure 2. Growth of publications on charged particle activation analysis

burst upon the world in the late 1950's and because of its seeming potential for practical application grew quite rapidly. (Td = 2.1 y, Figure 3.) Disillusionment was also rapid, however, and the field's growth has now slowed to a Td of eight years. Also shown in Figure 3 is the plot for papers on solidstate detectors. T h i s was and continues to be an extremely " h o t " field which has maintained its fantastic doubling time of about one year and has pushed through three decades of

T h e 14-MeV neutron generator was another " h o t " item in the early 1960's. As seen in Figure 4 (data from ref. 11), the first three or four years showed t h e rapid doubling time of 1.1 y. T h e n through the middle 1960's growth began to slow (Td = 2.3 y). Finally, in t h e late 1960's a n d early 1970's, Td lengthened further to about 6.4 y. These d a t a have been replotted on linear paper in Figure 5, and we have used poetic license in reducing Shakespeare's seven ages of m a n to four ages of generators.

Of Authors and Journals

been confirmed again! T h i s can be cal­ culated in another way by plotting the cumulative percent of publications vs. t h e cumulative percent of authors. T h i s shows t h a t 50% of all activation analysis publications are produced by about 13% of t h e total authors. Now in Figure 7 we look a t t h e jour­ nal distribution for papers in another subset of activation analysis: p r o m p t nuclear methods. T h i s is a rather se­ lect subset in t h a t the n u m b e r of pa­ pers is not overwhelming (thus easy to count!). As seen in Figure 7, four journals account for 40% of the papers; 16 journals account for 60%; and an additional 78 journals supply less t h a n 40%.

Citation Half-Lives T h e literature of activation analysis is growing with a doubling rate of 3.0 y (Figure 1). An interesting corollary to this is to calculate the decay (or half-life) of the references cited in re-

In 1926 A. J. Lotka propounded, and later workers confirmed, the observation now known as Lotka's law (12). This law states t h a t t h e n u m b e r of people producing η papers is pro­ portional to 1/n 2 . For example, within a certain time interval, if 100 authors produce one paper, only 25 will pro­ duce two; only 11 will produce three, etc. T h e n u m b e r of authors and pa­ pers per author are plotted for activa­ tion analysis in Figure 6. Lotka has

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caption for the period 1972-74. With an indicated half-life of 4.0 y, it is apparent t h a t the literature is decaying only slightly less rapidly t h a n it is growing. Finally, in Figure 10 we break the composite four-journal data of Figure 9 into its components. And to give a truly radiochemical flavor to this paper, we have further resolved the Radiochemical and Radioanalytical Letters data into two components: one long-lived (5-6 y) and one short (2.2 y). Quite probably the other journals would show a similar distribution were it to be made. T h e uniform halflife of about four years for all citations is impressive and interesting. C o m m e n t s and Conclusions

Figure 3. Growth of publications on forensic analysis and solid-state detectors Figure 6. Lotka's (inverse square) law activation analysis (time period: 19361970)

Figure 4. Growth of publications on activation analysis by 14-MeV neutron generators

Figure 7. Distribution of papers on prompt nuclear analysis (time period: 1950-19721 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16.

Figure 5. Four ages of neutron generators

J. Radioanal. Chem. Nucl. Instrum. Methods Trans. Am. Nucl. Soc. Anal. Chem. J. Appl. Phys. Int. J. Appi. Radiat. Isot. At. Energ. Appl. Phys. Lett. Anal. Chim. Acta Analyst Dokl.Akad. Nauk J. Geophys. Res. J. Phys. Chem. Solids Radiochem. Radioanal. Lett. Nature Can. J. Phys.

cent literature. Figure 8 shows such data collected from the Journal of Radioanalytical Chemistry; note t h a t the data are for all radioanalytical papers. From the figure one notes t h a t 85% of the references are less than 10 years old. In Figure 9 the radiochemist will recognize a decay curve—number of references vs. time. T h e data are from the four journals indicated in the

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T h e doubling time for activation analysis appears to be holding steady at three years; this is a little faster than one of its parents, nuclear physics, which has a Tj of between four and five (4). This can also be compared with Td values for other subsets of analytical chemistry (5, 6): amperometry (8.0 y), conductometry (6.4 y), electroanalytical (4.6 y), potentiometry (4.0 y), and voltammetry (2.8 y). Since the cumulative growth of activation analysis papers covers four decades (as of 1970), it seems unlikely t h a t the 3.0 y doubling rate could have continued much longer. A study of this latter period awaits completion. From the data presented here, one can surmise t h a t the 35 year-old scientist who thinks the literature was once more manageable and the 45 year-old who knows it are both correct. With a literature growth Tj of 3.0 y, a researcher who entered the field 10 years ago has seen a tenfold increase in published articles; the 45 year-old scientist has watched it increase by a factor of greater than 100! But for the scientist there is a silver lining, albeit only a plated one: most of the references he uses are from papers published during the preceding 5-10 years (Figure 8). This allows one to make an observation concerning the use of number of citations as an index of scientific excellence: Such citations do primarily reflect current productivity; presumably this is what management wants to measure. However, at least two objections to such use of citations can be made: Citations only are compiled for the first author, and basic papers or experiments are often not referenced. As pointed out by Goudsmit (13), many fundamental discoveries are known by the name of the experimenter (so-and-so's law, for example) and are mentioned by name only, not cited. T h e use of citations for evaluating technical performance remains a controversial subject; opposition to the idea probably follows an inverse

Figure 9. C o m p o s i t e decay c u r v e of radioanalytical r e f e r e n c e s Anal. Chem. Anal. Chim. Acta J. Radioanal. Chem. Radiochem. Radioanal. Lett. Figure 8. Decay of radioanalytical r e f e r e n c e s

square law: the farther one is from where the actual work is being done, the less the antipathy to citation counting. In a wry discussion Archibald Putt (14) has propounded his Law Governing the Value of Technical Publications:'The value of a technical article when first published is proportional to the sum of the prestige of its authors, but its ultimate value is proportional to the sum of the subsequent references to it. Pointing out that the clever author will ensure himself a multitude of citations by citing all his previous papers and developing a reciprocating coauthorship with a number of other authors who in turn will cite each other's work, Putt visualizes the ultimate journal article as one in which: "the prestige of the multiple-person 'authoring group' is so great that only the Abstract, Acknowledgments and Citations (to the authors' previous works) are needed. Citations would continue for several pages. Text is now superfluous and need not appear (nor, indeed, need it even be written)." Some interesting questions and subjects for further investigation and elaboration are suggested by the results presented here. For example, what is the relationship between prolific authors and citations and with what frequency are certain papers cited? But for many analytical chemists, the literature seems to be part of a technical problem rather than a

Figure 10. C o m p o n e n t r e s o l v e d d e c a y c u r v e of radioanalytical r e f e r e n c e s

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means to the solution. T h e paper explosion makes the task of following the literature almost impossible. Review articles, and to a very limited ext e n t bibliographies, may be helpful in combing data. B u t compiling a n d p u b lishing lists of titles and subjects often only adds to the problem. Again, however, like the validity of citations as an index of excellence, or for t h a t matter number of papers, the question of how best to handle the expanding universe of papers is beyond the scope of this report. [One recent suggestion, for example, is to use an electronic system to deliver research results in selected fields (15)]. W h a t we have done in this report is to document the growth and internal clockwork of one subfield of analytical chemistry. Recognition of the above-mentioned problems and others of equal intellectual and practi-

Tibor

Braun

Tibor B r a u n is presently visiting professor in the Department of Chemistry of the University of the West Indies, Kingston, Jamaica, on a one-year leave from the Institute of Inorganic and Analytical Chemistry of the L. Eötvös University, Budapest, Hungary. He received a diploma in chemistry from the V. Babes University, Cluj, Romania, in 1954 and received his CSc (PhD) in Budapest, Hungary, in 1967. His current research interests include radiochemical analysis, trace element separation and preconcentration, and new analytical sorbents. He has authored more than 50 research papers on these topics and is coauthor of two books on radiometric titrations and isotope dilution analysis and coeditor of a monograph on extraction chromatography. Dr. Braun is founder and coeditor of the Journal ofRadioanalytical Chemistry and οι Radiochemi­ cal and Radioanalytical Letters. He received (together with J. Tolgyessy)

cal interest has been for us an intrigu­ ing by-product of this study. We hope to look at some of these questions in detail as time permits, and we invite other scientists in other subfields to examine their literature and t o use their ingenuity in devising answers to the many problems posed by rapid lit­ erature growth.

References (1) D. J. de Soila Price, "Little Science, Big Science", Columbia Univ. Press, New York, N.Y., 1963. (2) D. J. de Soila Price, "Science Since Ba­ bylon", Yale Univ. Press, New Haven, Conn., 1961. (3) J. R. Cole and S. Cole, Science, 178, 368 (1972); N. Wade, ibid., 188, 429 (1975); J. R. Cole and S. Cole, "Social Stratification in Science", Univ. of Chi­ cago Press, Chicago, 111., London, En­ gland, 1973.

W. S. Lyon the 1975 Hevesy Medal for contribu­ tions to radioanalytical chemistry.

W. S. Lyon is head of the Advanced Methodology Section of the Analytical Chemistry Division at Oak Ridge Na­ tional Laboratory. He has coauthored Nucleonics for the Annual Reviews

issue of ANALYTICAL

CHEMISTRY

since 1966 and has over 100 other pub­ lished papers. T h e editor of "Guide to Activation Analysis" (Van Nostrand, 1964) and author of the soonto-be-published "Trace Element Mea­ surements at the Coal Fired Steam P l a n t " (CRC Press, 1977), he is on the editorial board of two international journals, program chairman of the Isotopes and Radiation Division of the ANS, and is active in the ACS. Activa­ tion analysis, nuclear measurements, and radiochemistry have been the principal objects of his attention, but he has been intrigued by, looked into,

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(4) H. W. Menard, "Science: Growth and Change", Harvard Univ. Press, Cam­ bridge, Mass., 1971. (5) R. R. Brooks and L. E. Smythe, Talanta, 22, 495 (1975). (6) T. Braun, ibid., 23, 743 (1976). (7) V. V. Nalimov and Z. M. Mulchenko, Naukometriya (Scientometrics), Izd. Nauka, Moscow, USSR, 1969. (8) G. M. Dobrov, Nauka Nauke (Science of Science), Naukova Dumka, Kiev, USSR, 1970. (9) W. S. Lyon, Anal. Chem., 45, 386A (1973). (10) G. J. Lutz, R. J. Boreni, R. S. Maddock, and W. W. Meinke, "Activation Analysis: A Bibliography", Part I, NBS Technical Note 467,1971. (11) R. Van Grieren and J. Hoste, Eurisotop Off. Inf. BookL, 65, 281 (1972). (12) A. J. Lotka, J. Wash. Acad. Sci., 16, 317 (1926). (13) S. A. Goudsmit, Science, 183,28 (1974). (14) A. Putt, Res. Develop., ρ 12 (Sept. 1976). (15) Sci. News, 111,153(1977).

Erno

Bujdoso

and written about a number of other subjects including biorhythm, the va­ lidity of aptitude tests to predict suc­ cess in technical training, problems in following instructions, and in this article, scientometrics. Erno Bujdoso is head of the Re­ search, Engineering and Prime Con­ tracting Centre of the Hungarian Alu­ minum Corp., Budapest, Hungary. His research interests include the applica­ tion of nuclear methods, i.e., radiochemistry, activation analysis, and tracer techniques in the aluminum in­ dustry, and scientometrics. Dr. Buj­ doso is an associate editor of Radio­ chemical and Radioanalytical Letters and an editor of The Journal of Ra­ dioanalytical Chemistry. He gradu­ ated from L. Kossuth University in Debrecen, Hungary, receiving his P h D in 1958, after which he joined the Nu­ clear Research Institute of the Hun­ garian Academy of Sciences.