De onderstaande lijst van publicaties is op omgekeerde chronologische volgorde en gescheiden per jaar.

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[preprint]: een PDF van de preprint van het artikel

Verder kan door op deze knop te drukken de abstract van de publicatie op de pagina worden getoond:



Bossema, F.G., Burger, P., Bratton, L., Challenger, A., Adams, R.C., Sumner, P., Schat, J., Numans, M.E., Smeets, I. (2019). Expert quotes and exaggeration in health news: a retrospective quantitative content analysis. [version 1; peer review: 1 approved with reservations]. Wellcome Open Res 4, 56. doi: 10.12688/wellcomeopenres.15147.1
[link] [preprint]  


This research is an investigation into the role of expert quotes in health news, specifically whether news articles containing a quote from an independent expert are less often exaggerated than articles without such a quote.


Retrospective quantitative content analysis of journal articles, press releases, and associated news articles was performed. The investigated sample are press releases on peer-reviewed health research and the associated research articles and news stories. Our sample consisted of 462 press releases and 668 news articles from the UK (2011) and 129 press releases and 185 news articles from The Netherlands (2015). We hand-coded all journal articles, press releases and news articles for correlational claims, using a well-tested codebook. The main outcome measures are types of sources that were quoted and exaggeration of correlational claims. We used counts, 2×2 tables and odds ratios to assess the relationship between presence of quotes and exaggeration of the causal claim.


Overall, 99.1% of the UK press releases and 84.5% of the Dutch press releases contain at least one quote. For the associated news articles these percentages are: 88.6% in the UK and 69.7% in the Netherlands. Authors of the study are most often quoted and only 7.5% of UK and 7.0% of Dutch news articles contained a new quote by an expert source, i.e. one not provided by the press release. The relative odds that an article without an external expert quote contains an exaggeration of causality is 2.6.


The number of articles containing a quote from an independent expert is low, but articles that cite an external expert do contain less exaggeration.

Willems, S.J.W., Albers, C.J., Smeets, I. (2019). Variability in the interpretation of Dutch probability phrases – a risk for miscommunication. arXiv preprint arXiv:1901.09686.

Verbal probability phrases are often used to express estimated risk. In this study, focus was on the numerical interpretation of 29 Dutch probability and frequency phrases, including several complementary phrases to test (a)symmetry in their interpretation. Many of these phrases had not been studied before. The phrases were presented in the context of ordinary situations. The survey was distributed among both statisticians and non-statisticians with Dutch as their native language.
The responses from 881 participants showed a large variability in the interpretation of Dutch phrases, and the neutral contexts seemed to have no structural influence. Furthermore, the results demonstrated an asymmetry in the interpretation of Dutch complementary phrases. The large variability of interpretations was found among both statisticians and non-statisticians, and among males and females, however, no structural differences were found between the groups.
Concluding, there is a large variability in the interpretation of verbal probability phrases, even within sub-populations. Therefore, verbal probability expressions may be a risk for miscommunication.

Venhuizen, G. J., Hut, R., Albers, C., Stoof, C. R., & Smeets, I. (2019). Flooded by jargon: How the interpretation of water-related terms differs between hydrology experts and the general audience. Hydrology and Earth System Sciences Discussions, 23(1), 393-403. doi:10.5194/hess-2018-297
[link] [PDF]  

Communication about water-induced hazards (such as floods, droughts or levee breaches) is important, in order to keep their impact as low as possible. However, sometimes the boundary between specialized and non-specialized language can be vague. Therefore, a close scrutiny of the use of hydrological vocabulary by both experts and laypeople is necessary.
In this study, we compare the expert and layperson definitions of 22 common terms and pictures related to water and water hazards, to see where misunderstandings might arise both in text and pictures. Our primary objective is to analyze the degree of agreement between experts and laypeople in their definition of the used terms. In this way, we hope to contribute to improving the communication between these groups in the future. Our study was based on a survey completed by 34 experts and 119 laypeople.
Especially concerning the definition of words related to water there are some profound differences between experts and laypeople: words like “river” and “river basin” turn out to have a thoroughly different interpretation between the two groups. Concerning the pictures, there is much more agreement between the groups.

Vries, M. D., Land-Zandstra, A., & Smeets, I. (2019). Citizen Scientists’ Preferences for Communication of Scientific Output: A Literature Review. Citizen Science: Theory and Practice, 42. doi:10.5334/cstp.136
[link] [PDF]  

Many citizen science developers agree that participants in citizen science projects need to receive feedback on project outputs and that they should be recognized in results and publications. However, little research has thoroughly investigated the extent to which citizen scientists find communication of scientific output to be important. Citizen science studies rarely investigate this topic as their main goal. Therefore, we conducted a review on participants’ preferences for communication of data, findings, and scientific publications in papers that focus on participant motivation but which also contain relevant evidence about communication in parts of the results. We reviewed 32 peer-reviewed papers that contained relevant evidence in quantitative analyses (e.g., Likert scale-type questions) or in qualitative analyses (e.g., interviews with participants).
From this review, we conclude that participants value accessibility of their collected data, communication of project findings, and acknowledgement in publications. Taking this into account can pay off, as sharing data and findings can enhance the motivation of participants to engage in the project, thereby sustaining their participation, imparting the feeling that they spent their time well, and increasing a project’s learning impact. Some practical and ethical issues such as privacy concerns, however, need to be taken into account. This literature review is the first to provide an overview of citizen scientists’ preferences for communication of scientific output, and is a starting point for further research that should investigate the impact of different options for data sharing and communication of findings to participants.


Smeets, I. (2018). What Do People Like about Mathematics? Adults Learning Mathematics: An International Journal, 13, 7.
[link] [PDF]

In this discussion paper we look at questions that adults have about numbers. Many of their questions are not about pure mathematics, but about personal, cultural or societal issues. We discuss how to connect mathematical topics with things people are interested in, based on theoretic knowledge from the field of science communication. We focus on using narratives to make mathematics more personal, how to use games as demonstrations and different ways to present the same mathematical problem in different societal

Schat, J., Bossema, F.G., Numans, M.E., Smeets, I., Burger, J.P. (2018). Overdreven gezondheidsnieuws. Relatie tussen overdrijving in academische persberichten en in nieuwsmedia. Nederlands Tijdschrift voor Geneeskunde, 162, 5.
[link] [PDF]


Bepalen hoe vaak pers- en nieuwsberichten overdrijvingen bevatten en onderzoeken waar in het traject tussen wetenschappelijke publicatie en nieuwsbericht deze overdrijving ontstaat.


Retrospectieve kwantitatieve inhoudsanalyse.


We analyseerden persberichten over gezondheidsonderzoek die door de Nederlandse universiteiten en universitaire medische centra in 2015 waren uitgebracht (n = 129) en de aan die persberichten gerelateerde berichten in de nieuwsmedia (n = 185).


20% van de persberichten en 29% van de nieuwsberichten bevatten overdrijving van de conclusie of causale claim. Expliciet gezondheidsadvies werd indien aanwezig overdreven in 7% van de persberichten en in 10% van de nieuwsberichten. Wanneer het persbericht een overdrijving van de conclusie of causale claim bevatte, stond in 92% van de gerelateerde nieuwsberichten dezelfde overdrijving. Als de conclusie in het persbericht niet overdreven was, was 6% van de nieuwsberichten overdreven. De relatieve kans op overdreven nieuws bij een overdreven persbericht was 16,08 (95%-BI: 7,35-35,18). Bij overdreven persberichten hoorde vaker een nieuwsbericht. De relatieve kans op een nieuwsbericht bij een overdreven persbericht tegenover een niet-overdreven persbericht was 1,45 (95%-BI: 1,02-2,04).


Overdrijving in gezondheidsnieuws gaat sterk gepaard met overdrijving in het oorspronkelijke persbericht en komt voor bij meer dan 1 op de 5 artikelen. Het monitoren en zo nodig verbeteren van de nauwkeurigheid en juistheid van academische persberichten lijken een belangrijke stap om de kwaliteit van gezondheidsnieuws te verhogen.


Smeets, I. (2017). Gelijk hebben én krijgen. Vakmedianet.
[link] [PDF]

Tijdens het voorgesprek voor deze Jan de Kroes-lezing vertelde de organisatie dat veiligheidsexperts vaak mopperen dat hun leidinggevenden niet naar hen luisteren. Terwijl zij toch echt gelijk hebben, zij weten immers precies wat de risico’s zijn. Helaas blijkt het vaak lastig om anderen te overtuigen, zelfs als de feiten aan je kant staan.


Hut, R. Land-Zandstra, A.M., Smeets, I., Stoof, C.R. (2016). Geoscience on television: a review of science communication literature in the context of geosciences. Hydrology and Earth System Sciences, 20(6), 2507-2518. doi:10.5194/hess-20-2507-2016
[link] [PDF]

Geoscience communication is becoming increasingly important as climate change increases the occurrence of natural hazards around the world. Few geoscientists are trained in effective science communication, and awareness of the formal science communication literature is also low. This can be challenging when interacting with journalists on a powerful medium like TV. To provide geoscience communicators with background knowledge on effective science communication on television, we reviewed relevant theory in the context of geosciences and discuss six major themes: scientist motivation, target audience, narratives and storytelling, jargon and information transfer, relationship between scientists and journalists, and stereotypes of scientists on TV. We illustrate each theme with a case study of geosciences on TV and discuss relevant science communication literature. We then highlight how this literature applies to the geosciences and identify knowledge gaps related to science communication in the geosciences. As TV offers a unique opportunity to reach many viewers, we hope this review can not only positively contribute to effective geoscience communication but also to the wider geoscience debate in society.


Bosma, W., & Smeets, I. (2013). Finding simultaneous Diophantine approximations with prescribed quality. The Open Book Series, 1(1), 167-185. doi:10.2140/obs.2013.1.167
[link] [PDF]

We give an algorithm that finds a sequence of approximations with Dirichlet coefficients bounded by a constant only depending on the dimension. The algorithm uses LLL lattice basis reduction. We present a version of the algorithm that runs in polynomial time of the input.


Kraaikamp, C., & Smeets, I. (2011). Sharp bounds for symmetric and asymmetric diophantine approximation. Chinese Annals of Mathematics, Series B, 32(2), 303-320. doi: 10.1007/s11401-011-0629-4
[link] [PDF]

In 2004, Tong found bounds for the approximation quality of a regular continued fraction convergent to a rational number, expressed in bounds for both the previous and next approximation. The authors sharpen his results with a geometric method and give both sharp upper and lower bounds. The asymptotic frequencies that these bounds occur are also calculated.


Smeets, I. (2010). On continued fraction algorithms (Doctoral dissertation, Mathematical Institute, Faculty of Science, Leiden University).
[link] [PDF]

Is there a good continued fraction approximation between every two bad ones? What is the entropy of the natural extension for alpha-Rosen fractions? How do you find multi-dimensional continued fractions with a guaranteed quality in polynomial time? These, and many more, questions are answered in this thesis.

Kraaikamp, C., Schmidt, T. A., & Smeets, I. (2010). Natural extensions for α-Rosen continued fractions. Journal of the Mathematical Society of Japan, 62(2), 649-671. doi: 10.2969/jmsj/06220649
[link] [PDF]

We give natural extensions for the α-Rosen continued fractions of Dajani et al. for a set of small α values by appropriately adding and deleting rectangles from the region of the natural extension for the standard Rosen fractions. It follows that the underlying maps have equal entropy.


Kraaikamp, C., & Smeets, I. (2009). Approximation Results for alpha-Rosen Fractions. arXiv preprint arXiv:0912.1749.

In this article we generalize Borel’s classical approximation results for the regular continued fraction expansion to the alpha-Rosen fraction expansion, using a geometric method. We give a Haas-Series-type result about all possible good approximations for the alpha for which the Legendre constant is larger than the Hurwitz constant.

Smeets, I., Lenstra, A., Lenstra, H., Lovász, L., & van Emde Boas, P. (2009). The History of the LLL-algorithm. In The LLL Algorithm (pp. 1-17). Springer, Berlin, Heidelberg. doi: 10.1007/978-3-642-02295-1_1
[link] [PDF]

The 25th birthday of the LLL-algorithm was celebrated in Caen from 29th June to 1st July 2007. The three day conference kicked off with a historical session of four talks about the origins of the algorithm. The speakers were the three L’s and close bystander Peter van Emde Boas. These were the titles of their talks.

A tale of two papers – Peter van Emde Boas.
The early history of LLL – Hendrik Lenstra.
The ellipsoid method and basis reduction – László Lovász.
Polynomial factorization and lattices in the very early 1980s – Arjen Lenstra.

This chapter is based on those talks, conversations with these four historic characters, the notes that Peter van Emde Boas and Arjen Lenstra wrote for the preproceedings, and many artifacts from the phenomenal archive of Van Emde Boas.


Kraaikamp, C., Schmidt, T. A., & Smeets, I. (2007). Tong’s spectrum for Rosen continued fractions. Journal de théorie des nombres de Bordeaux, 19(3), 641-661. doi: 10.5802/jtnb.606
[link] [PDF]

In the 1990s, J.C. Tong gave a sharp upper bound on the minimum of k consecutive approximation constants for the nearest integer continued fractions. We generalize this to the case of approximation by Rosen continued fraction expansions. The Rosen fractions are an infinite set of continued fraction algorithms, each giving expansions of real numbers in terms of certain algebraic integers. For each, we give a best possible upper bound for the minimum in appropriate consecutive blocks of approximation coefficients. We also obtain metrical results for large blocks of “bad” approximations.