Interpreting correlations between citation counts and other indicators

This is an accepted manuscript of an article published by Springer in Scientometrics on 09/05/2016, available online: https://doi.org/10.1007/s11192-016-1973-7 The accepted version of the publication may differ from the final published version.Altmetrics or other indicators for the impact of academic outputs are often correlated with citation counts in order to help assess their value. Nevertheless, there are no guidelines about how to assess the strengths of the correlations found. This is a problem because this value affects the conclusions that should be drawn. In response, this article uses experimental simulations to assess the correlation strengths to be expected under various different conditions. The results show that the correlation strength reflects not only the underlying degree of association but also the average magnitude of the numbers involved. Overall, the results suggest that due to the number of assumptions that must be made in practice it will rarely be possible to make a realistic interpretation of the strength of a correlation coefficient

Measuring publication diversity among the most productive scholars: how research trajectories differ in communication, psychology, and political science

Examining research patterns across scientific fields constitutes a growing research enterprise to understand how global knowledge production unfolds. However, scattered empirical evidence has casted light on how the publication diversity of the most productive scholars differ across disciplines, considering their gender and geographical representation. This study focuses on the most prolific scholars across three fields (Communication, Political Science, and Psychology), and examine all journals where they have published. Results revealed the most common journals in which prolific scholars have appeared and showed that Communication scholars are more prone to publish in Political Science and Psychology journals than vice-versa, while psychologists' largely neglect them both. Our findings also demonstrate that males and US scholars are over-represented across fields, and that neither the field, gender, geographic location, or the interaction between gender and geographic location has a significant influence over publication diversity. The study suggests that prolific scholars are not only productive, but also highly diverse in the selection of the journals they publish, which directly speaks to both the heterogeneity of their research contributions and target readers

Scientists' bounded mobility on the epistemic landscape

Despite persistent efforts in revealing the temporal patterns in scientific careers, little attention has been paid to the spatial patterns of scientific activities in the knowledge space. Here, drawing on millions of papers in six disciplines, we consider scientists' publication sequence as "walks" on the quantifiable epistemic landscape constructed from large-scale bibliometric corpora by combining embedding and manifold learning algorithms, aiming to reveal the individual research topic dynamics and association between research radius with academic performance, along their careers. Intuitively, the visualization shows the localized and bounded nature of mobile trajectories. We further find that the distributions of scientists' transition radius and transition pace are both left-skewed compared with the results of controlled experiments. Then, we observe the mixed exploration and exploitation pattern and the corresponding strategic trade-off in the research transition, where scientists both deepen their previous research with frequency bias and explore new research with knowledge proximity bias. We further develop a bounded exploration-exploitation (BEE) model to reproduce the observed patterns. Moreover, the association between scientists' research radius and academic performance shows that extensive exploration will not lead to a sustained increase in academic output but a decrease in impact. In addition, we also note that disruptive findings are more derived from an extensive transition, whereas there is a saturation in this association. Our study contributes to the comprehension of the mobility patterns of scientists in the knowledge space, thereby providing significant implications for the development of scientific policy-making.Comment: article paper, 47 pages, 29 figures, 4 table

Domestic researchers with longer careers generate higher average citation impact but it does not increase over time

© The Authors. Published by MIT Press. This is an open access article available under a Creative Commons licence. The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.1162/qss_a_00132Information about the relative strengths of scholars is needed for the efficient running of knowledge systems. Since academic research requires many skills, more experienced researchers might produce better research and attract more citations. This article assesses career citation impact changes 2001-2016 for domestic researchers (definition: first and last Scopus journal article in the same country) from the twelve nations with most Scopus documents. Careers are analysed longitudinally, so that changes are not due to personnel evolution, such as researchers leaving or entering a country. The results show that long term domestic researchers do not tend to improve their citation impact over time but tend to achieve their average citation impact by their first or second Scopus journal article. In some countries, this citation impact subsequently declines. These longer-term domestic researchers have higher citation impact than the national average in all countries, however, whereas scholars publishing only one journal article have substantially lower citation impact in all countries. The results are consistent with an efficiently functioning researcher selection system but cast slight doubt on the long-term citation impact potential of long-term domestic researchers. Research and funding policies may need to accommodate these patterns when citation impact is a relevant indicator

Jätkusuutlikud teadlaskarjääri kontseptsioonid ja mudelid Eesti kontekstis : lõpparuanne

Uuringu tellis SA Eesti Teadusagentuur. Uuringu tegi Eesti Teaduste Akadeemia koostöös Tallinna Ülikooli ja Tallinna Tehnikaülikooliga.Esitatakse ülevaade kaasaegsete teadlaskarjääri mudelite põhimõtetest, peamistest elemen-tidest, nende teisenemisest viimastel aastakümnetel ning erinevate mudelite rakendamisel ilmnenud kitsaskohtadest teaduskirjanduses 2011–2017 ilmunud artiklite, üksikutes riikides rakendatud mudelite võrdlevate ülevaadete ja neis esitatud materjalide ekspertarutelude alusel. Sama andmestiku alusel analüüsitakse teadlaskarjääride kujunemise dünaamikat ja teadlaskarjääri iseärasuste seoseid teadlaste mõjukuse ja teadussüsteemi toimimisega. Tõdetakse, et optimaalne teadlaskarjääri mudel on üks teadmispõhise ühiskonna tugedest ning ideaalis mehhanism, mis realiseerib parimal moel teadlaste potentsiaali ühiskonna vaja-dusteks. Identifitseeritakse Eesti jaoks sobivate mudelite kontseptuaalsed alused, soovitus-likud ülesehituse printsiibid ja võimalikud proportsioonid ning ajaline dünaamika. Leitakse, et Eestis tuleks käivitada selge ja läbipaistev ning samas piisavalt paindlik ja erisusi aktsepteeriv karjäärimudel, mis annaks julgustava signaali võimekatele noorteadlastele, võimaldaks selekteerida välja säravad teadlased juba suhteliselt varases staadiumis ning aitaks kaasa võrdsete võimaluste tagamisele. Mudeli eesmärk on väga häid tippe Eesti akadeemilisele maastikule juurde saada ja neid siin hoida. Sellise mudeli selgroona soovitatakse luua tenuurisüsteem (tähtajalised ametikohad tenuu-rirajal, millele järgnevad tähtajatud tenuuri ametikohad) olemasoleva süsteemi täiendusena. Süsteem peaks haarama väikese hulga tippteadlasi (ligikaudu 1/5 teadlastest ja õppejõudu-dest) ning toimima lävendipõhiselt õigustatud ootuse printsiibi alusel. Tenuurisüsteem eel-dab stabiilset rahastust, mis peab olema garanteeritud asutuste, mitte teadlaste endi ega nende allüksuste poolt. Tenuurisüsteemi põhimõtted tuleks sätestada seaduse tasemel, jättes ülikoolidele ulatusliku otsustusõiguse detailide kujundamisel. Jõutakse järeldusele, et taoline süsteem teeb teadlaskarjääri atraktiivseks, pakkudes tenuuri jõudnutele töökohakindlust ja rahvusvaheliselt konkurentsivõimelisi töötingimusi. Paralleel-selt tenuurisüsteemiga tuleb käigus hoida laiapõhjaline akadeemiline kogukond, mille ole-masolu tagab teadusmaastiku paindlikkuse. Analüüsitakse tenuuri tüüpi mudelite spetsiifikat teadlaste mobiilsuse, tippteaduse toeta-mise, teaduskoostöö kujunemise ja pärssivate tegurite seisukohalt. Antakse ülevaade soolise ebavõrdsuse problemaatikast karjäärimudeli kontekstis. Peetakse vajalikuks lähtuda teadlas-te soorituse hindamisel nende saavutustest selle aja vältel, mil nad on olnud aktiivselt tege-vad teadusmaastikul. Formuleeritakse soovitused karjääri üksikute elementide rakendamiseks Eesti tingimustes. Skitseeritakse tenuurisüsteemi rahastamise võimalused. Leitakse, et süsteemi tõrgeteta funktsioneerimiseks on vaja tagada õigeaegne väärikas väljumine nii, et pensionile jäämisega ei kaasne olulist elukvaliteedi langust. Kirjeldatakse võimalusi kujundada Eestis laiendatud akadeemiline tööturg. Soovitatakse jätkata tööstusdoktorantuuri institutsionaliseerimist ning käivitada teemapõhise uurija-professori institutsioon.The principles of contemporary research career models are outlined together with descriptions of their chief elements, modifications in the recent past, and known bottlenecks. The study is based on research papers published in scholarly journals in 2011–2017, comparative surveys of various models, and expert discussions over materials from these sources. The same dataset serves as the basis for analysing the dynamics of research career formation and links of research career peculiarities with researchers’ scientific prestige and functionality of the R&D system. An optimal research career model is found to be among the cornerstones of a knowledge-based society. Ideally, it is also a transfer mechanism of scientists’ capacity into practices meeting societal needs in the best possible way. The conceptual framework, recommended basic principles, as well as possible proportions of models suitable for Estonia are identified. The best suited career model to be implemented in Estonia has to be clear and transparent and, at the same time, sufficiently flexible and exception-tolerant. It is expected to communicate a motivating message to talented young scientists, enable creaming off excellent researchers in a relatively early stage of their careers, and contribute to promoting equal opportunities. The chief aim of the model is to attract the very best (top) scientists into the Estonian academic landscape and to keep them here. It is recommended that the core of such a model is formed by a tenure system (temporary positions on the tenure track followed by permanent tenure positions), launched as an extension to the currently existing R&D system. Desirably, the tenure system should encompass a relatively small cohort of top scientists (about 1/5 of research scientists and university teachers). Career paths in the tenure system should be threshold-based and follow the principle of legitimate expectation. Stable funding is an undisputed prerequisite for the tenure system and must be the responsibility of the entire institution. While the principles of the tenure system should be established by law, it makes good sense to give universities a wide span of control for determining the details. In all probability this kind of a system will make research careers attractive, offering enhanced job security and internationally competitive working conditions to the successful candidates. A broad-based academic community has to be upheld in parallel with the tenure system to ensure the flexibility of the research landscape. The specific features of tenure-type models are analysed with respect to research mobility, fostering of cutting edge science, evolution of research collaboration, and hindering factors. Also, the issues of gender inequality in context of career models are described. For evaluation of researchers’ performance it would be fair to take into account their achievements during the period of time when they were actively involved in the research. Recommendations for implementing single elements of such a system in Estonia are formulated and possible sources for its funding are indicated. Smooth functioning of the system is guaranteed only if the researchers’ exit occurs in a timely and dignified manner. The possible solutions for shaping an extended academic labour market in Estonia are described. Continuing the institutionalisation of the so-called industrial PhD education and launching topical Academy Research Professors’ institution are recommended.Tööd rahastatakse „Valdkondliku teadus- ja arendustegevuse tugevdamise (RITA)“ tegevuse 4 raames Euroopa Regionaalarengu Fondist