arXiv subjects

Wojciech Roszka

Publications and source records attributed to Wojciech Roszka.

11 recordsLinked to original sources

arXiv2026

Success in Science: How Global Prestige Organizes Careers

This article analyzes the structure of perceived academic success. We combine survey data from 10,848 Polish scientists with their Scopus bibliometric data at the individual level. We use polychoric correlations, exploratory factor analysis, network modeling (EBICglasso), and generalized linear mixed models in ordinal and binary forms. Our results show that academic success is multidimensional, with a clear core. This core is global publication prestige. Publishing in top international journals is the node with the highest centrality, and it is connected to other career dimensions, such as citations and international collaboration. Publications in top national journals, in contrast, are peripheral. The threshold structure of the scale indicates a selection effect. The definition of success is globally oriented and strongly tied to the hierarchy of international journals.

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arXiv2026

Top performers and top journals: Persistent concentration in scientific publishing

In this research, we analyze the relationship between publishing productivity and access to highly prestigious journals, treating publishing in top journals as a stratification mechanism selecting publishing elites. We study N = 144,314 Polish scientists publishing for 30 years (1992-2021) and their Nart = 433,546 unique research articles published in the period. Using bibliometric data from Scopus, we compare the scientists belonging to the top productivity decile (the upper 10%, termed top performers) and the remaining population of scientists (90%) by discipline and period (five six-year periods). We measure the share of publications in prestigious segments of journals, with particular reference to the 90th-99th percentiles, and we use nonlinear journal prestige-normalized productivity. Our results indicate that access to top journals (defined as the top 10% of journals indexed in Scopus) is powerfully and permanently concentrated in the group of top performers in all disciplines and periods studied. The differences between top performers and the other scientists are primarily of a qualitative nature: they are seen almost exclusively at the top of the journal hierarchy rather than in its bottom or middle segments. Our logistic regression models indicate the complementarity of quantity and quality: publishing intensity increases the probability of membership in the elite segment of top performers, especially when it is coupled with publishing in prestigious journals. Our results suggest that top journals function as selection gates to academic careers and that they function as durable mechanisms of elite reproduction in science.

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arXiv2025

International Research Collaboration Among Top Performers: A Gender Gap Persists

We studied gender differences among Polish top performers (the upper 10% of scientists in terms of research productivity) in international research collaborations in 15 STEMM disciplines and over time. We examined five 6-year periods from 1992 to 2021. We operationalized international research collaboration by using international publication co-authorships in Scopus and used a sample of 152,043 unique Polish authors and their 587,558 articles published in 1992-2021. Our data show that a gender gap in international collaboration by top performers (and among the whole population of scientists) steadily widened: the gap was smallest in the early 1990s and grew over the next 30 years. Among top performers, internationalization intensity in four of the disciplines (AGRI, BIO, ENVI, and MED) was higher for men than for women. To capture the multidimensional nature of international research collaboration, we estimated a fractional logistic regression model with fixed effects that confirmed a persisting moderate but statistically significant international collaboration gender gap among top performers. We found an approximately 11% higher probability of international collaboration by men top performers compared with women top performers. Reflections on bibliometric-driven studies are offered.

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arXiv2024

Top Research Performance Over Three Decades: A Multidimensional Micro-Data Approach

In this research, the contributions of a highly productive minority of scientists to the national Polish research output over the past three decades (1992-2021) is explored. In almost all previous research, the approaches to high research productivity are missing the time component. Cross-sectional studies were not complemented by longitudinal studies: Scientists comprising the classes of top performers have not been tracked over time. Three classes of top performers (the upper 1%, 5%, and 10%) are examined, and a surprising temporal stability of productivity patterns is found. The 1/10 and 10/50 rules consistently apply across the three decades: The upper 1% of scientists, on average, account for 10% of the national output, and the upper 10% account for almost 50% of total output, with significant disciplinary variations. The Relative Presence Index (RPI) we constructed shows that men are overrepresented and women underrepresented in all top performers classes. Top performers are studied longitudinally through their detailed publishing histories, with micro-data coming from the raw Scopus dataset. Econometric models identify the three most important predictors that change the odds ratio estimates of membership in the top performance classes: gender, academic age, and research collaboration. The downward trend in fixed effects over successive six-year periods indicates increasing competition in academia. A large population of all internationally visible Polish scientists (N=152,043) with their 587,558 articles is studied.

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arXiv2024

Are Scientists Changing their Research Productivity Classes When They Move Up the Academic Ladder?

We approach productivity in science in a longitudinal fashion: We track careers over time, up to 40 years. We first allocate scientists to decile-based publishing productivity classes, from the bottom 10% to the top 10%. Then, we seek patterns of mobility between the classes in two career stages: assistant professorship and associate professorship. Our findings confirm that radically changing publishing productivity levels (upward or downward) almost never happens. Scientists with a very weak past track record in publications emerge as having marginal chances of becoming scientists with a very strong future track record across all science, technology, engineering, mathematics, and medicine (STEMM) fields. Hence, our research shows a long-term character of careers in science, with publishing productivity during the apprenticeship period of assistant professorship heavily influencing productivity during the more independent period of associate professorship. We use individual-level microdata on academic careers (from a national registry of scientists) and individual-level metadata on publications (from the Scopus raw dataset). Polish associate professors tend to be stuck in their productivity classes for years: High performers tend to remain high performers, and low performers tend to remain low performers over their careers. Logistic regression analysis powerfully supports our two-dimensional results. We examine all internationally visible Polish associate professors in five fields of science in STEMM fields (N = 4,165 with N art = 71,841 articles).

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arXiv2023

The Young and the Old, the Fast and the Slow: A Large-Scale Study of Productivity Classes and Rank Advancement

We examined a large population of Polish science, technology, engineering, mathematics and medicine (STEMM) scientists (N = 16,083) to study rank advancement and productivity. We used two previously neglected time dimensions - promotion age and promotion speed - to construct individual biographical profiles and publication profiles. We used a classificatory approach and the new methodological approach of journal prestige-normalized productivity. All scientists were allocated to different productivity, promotion age, and promotion speed classes (top 20%, middle 60%, and bottom 20%). The patterns were consistent across all disciplines: scientists in young promotion age classes (and fast promotion speed classes) in the past were currently the most productive. In contrast, scientists in old promotion age classes (and slow promotion speed classes) in the past were currently the least productive. In the three largest disciplines, the young-old promotion age productivity differential for associate professors was 100-200% (150-200% for full professors); and the fast-slow promotion speed productivity differential for associate professors was 80-150% (100-170% for full professors). Our results were confirmed by a regression analysis in which we found odds ratio estimates of membership in top productivity classes. We combined data collected from the national register of all Polish scientists and scholars (N = 99,935) and publication metadata on all Polish articles indexed in Scopus (N = 935,167).

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arXiv2023

Academic vs. Biological Age in Research on Academic Careers: A Large-scale Study with Implications for Scientifically Developing Systems

Biological age is an important sociodemographic factor in studies on academic careers (research productivity, scholarly impact, and collaboration patterns). It is assumed that the academic age, or the time elapsed from the first publication, is a good proxy for biological age. In this study, we analyze the limitations of the proxy in academic career studies, using as an example the entire population of Polish academic scientists visible in the last decade in global science and holding at least a PhD (N = 20,569). The proxy works well for science, technology, engineering, mathematics, and medicine (STEMM) disciplines; however, for non-STEMM disciplines (particularly for humanities and social sciences), it has a dramatically worse performance. This negative conclusion is particularly important for systems that have only become recently visible in global academic journals. The micro-level data suggest a delayed participation of social scientists and humanists in global science networks, with practical implications for predicting biological age from academic age. We calculate correlation coefficients, present contingency analysis of academic career stages with academic positions and age groups, and create a linear multivariate regression model. Our research suggests that in scientifically developing countries, academic age as a proxy for biological age should be used more cautiously than in advanced countries: ideally, it should be used only for STEMM disciplines.

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arXiv2023

Are Female Scientists Less Inclined to Publish Alone? The Gender Solo Research Gap

In solo research, scientists compete individually for prestige, sending clear signals about their research ability, avoiding problems in credit allocation, and reducing conflicts about authorship. We examine to what extent male and female scientists differ in their use of solo publishing across various dimensions. This research is the first to comprehensively study the 'gender solo research gap' among all internationally visible scientists within a whole national higher education system. We examine the gap through 'individual publication portfolios' constructed for each Polish university professor. We use the practical significance/statistical significance difference (based on the effect-size r coefficient) and our analyses indicate that while some gender differences are statistically significant, they have no practical significance. Using a partial effects of fractional logistic regression approach, we estimate the probability of conducting solo research. In none of the models does gender explain the variability of the individual solo publishing rate. The strongest predictor of individual solo publishing rate is the average team size, publishing in STEM fields negatively affects the rate, publishing in male-dominated disciplines positively affects it, and the influence of international collaboration is negative. The gender solo research gap in Poland is much weaker than expected: within a more general trend toward team research and international research, gender differences in solo research are much weaker and less relevant than initially assumed. We use our unique biographical, administrative, publication, and citation database ('Polish Science Observatory') with metadata on all Polish scientists present in Scopus (N=25,463) and their 158,743 Scopus-indexed articles published in 2009-2018, including 18,900 solo articles.

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arXiv2023

Once Highly Productive, Forever Highly Productive? Full Professors' Research Productivity from a Longitudinal Perspective

This longitudinal study explores persistence in research productivity over time. We examine the trajectories of the academic careers of 2,326 current full professors in 14 STEMM disciplines, studying their lifetime biographical histories and publication histories. Every full professor is compared in terms of productivity classes (top, middle, bottom) with their peers at earlier career stages. We used prestige-normalized productivity in which more weight is given to articles in high-impact than in low-impact journals, recognizing the highly stratified nature of academic science. Our results show that membership in top productivity classes is to a large extent determined by being in these classes earlier. Half of the current top productive full professors belonged to top productivity classes throughout their academic careers. Half of the top productive assistant professors continued as top productive associate professors, and half of the top productive associate professors continued as top productive full professors (52.6% and 50.8%). Top-to-bottom and bottom-to-top transitions in productivity classes occurred marginally. The combination of biographical and demographic data with raw Scopus publication data from the past 50 years (N=1 million) made it possible to assign all full professors retrospective to different productivity, promotion age, and promotion speed classes. In logistic regression models, two powerful predictors of belonging to the top productivity class for full professors were being highly productive as assistant professors and as associate professors (increasing the odds by 180% and 360%). Neither gender nor age (biological or academic) emerged as statistically significant.

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arXiv2022

Gender Disparities in International Research Collaboration: A Large-scale Bibliometric Study of 25,000 University Professors

In this research, we examine the hypothesis that gender disparities in international research collaboration differ by collaboration intensity, academic position, age, and academic discipline. The following are the major findings: (1) while female scientists exhibit a higher rate of general, national, and institutional collaboration, male scientists exhibit a higher rate of international collaboration, a finding critically important in explaining gender disparities in impact, productivity, and access to large grants. (2) An aggregated picture of gender disparities hides a more nuanced cross-disciplinary picture of them. (3) An analysis of international research collaboration at three separate intensity levels (low, medium, and high) reveals that male scientists dominate in international collaboration at each level. However, at each level, there are specific disciplines in which females collaborate more than males. Further (4), gender disparities are clearly linked with age. Until about the age of 40, they are marginal and then they begin to grow. Finally, we estimate the odds of being involved in international research collaboration using an analytical linear logistic model. The examined sample includes 25,463 internationally productive Polish university professors from 85 universities, grouped into 27 disciplines, who authored 159,943 Scopus-indexed articles.

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arXiv2022

Gender-Based Homophily in Research: A Large-Scale Study of Man-Woman Collaboration

We examined the male-female collaboration practices of all internationally visible Polish university professors (N = 25,463) based on their Scopus-indexed publications from 2009-2018 (158,743 journal articles). We merged a national registry of 99,935 scientists (with full administrative and biographical data) with the Scopus publication database, using probabilistic and deterministic record linkage. Our unique biographical, administrative, publication, and citation database (The Polish Science Observatory) included all professors with at least a doctoral degree employed in 85 research-involved universities. We determined what we term an individual publication portfolio for every professor, and we examined the respective impacts of biological age, academic position, academic discipline, average journal prestige, and type of institution on the same-sex collaboration ratio. The gender homophily principle (publishing predominantly with scientists of the same sex) was found to apply to male scientists - but not to females. The majority of male scientists collaborate solely with males; most female scientists, in contrast, do not collaborate with females at all. Across all age groups studied, all-female collaboration is marginal, while all-male collaboration is pervasive. Gender homophily in research-intensive institutions proved stronger for males than for females. Finally, we used a multi-dimensional fractional logit regression model to estimate the impact of gender and other individual-level and institutional-level independent variables on gender homophily in research collaboration.

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