Some modifications to the SNIP journal impact indicator

The SNIP (source normalized impact per paper) indicator is an indicator of the citation impact of scientific journals. The indicator, introduced by Henk Moed in 2010, is included in Elsevier's Scopus database. The SNIP indicator uses a source normalized approach to correct for differences in citation practices between scientific fields. The strength of this approach is that it does not require a field classification system in which the boundaries of fields are explicitly defined. In this paper, a number of modifications that will be made to the SNIP indicator are explained, and the advantages of the resulting revised SNIP indicator are pointed out. It is argued that the original SNIP indicator has some counterintuitive properties, and it is shown mathematically that the revised SNIP indicator does not have these properties. Empirically, the differences between the original SNIP indicator and the revised one turn out to be relatively small, although some systematic differences can be observed. Relations with other source normalized indicators proposed in the literature are discussed as well

Rivals for the crown: Reply to Opthof and Leydesdorff

We reply to the criticism of Opthof and Leydesdorff [arXiv:1002.2769] on the way in which our institute applies journal and field normalizations to citation counts. We point out why we believe most of the criticism is unjustified, but we also indicate where we think Opthof and Leydesdorff raise a valid point

Towards a new crown indicator: Some theoretical considerations

The crown indicator is a well-known bibliometric indicator of research performance developed by our institute. The indicator aims to normalize citation counts for differences among fields. We critically examine the theoretical basis of the normalization mechanism applied in the crown indicator. We also make a comparison with an alternative normalization mechanism. The alternative mechanism turns out to have more satisfactory properties than the mechanism applied in the crown indicator. In particular, the alternative mechanism has a so-called consistency property. The mechanism applied in the crown indicator lacks this important property. As a consequence of our findings, we are currently moving towards a new crown indicator, which relies on the alternative normalization mechanism

Severe Language Effect in University Rankings: Particularly Germany and France are wronged in citation-based rankings

We applied a set of standard bibliometric indicators to monitor the scientific state-of-arte of 500 universities worldwide and constructed a ranking on the basis of these indicators (Leiden Ranking 2010). We find a dramatic and hitherto largely underestimated language effect in the bibliometric, citation-based measurement of research performance when comparing the ranking based on all Web of Science (WoS) covered publications and on only English WoS covered publications, particularly for Germany and France.Comment: Short communication, 3 pages, 4 figure

Характеристика загрязнения прибрежных вод у Карадагского заповедника по данным оптических измерений

На основе анализа данных оптических наблюдений в рамках комплексных океанографических экспедиций, проведенных сотрудниками ИнБЮМ НАНУ и МГИ НАНУ 22, 23 мая 2007 г. и 21, 22 июля 2009 г. в прибрежных водах Черного моря у Карадагского заповедника, выполнены оценки загрязнения рассматриваемой акватории растворенным органическим веществом искусственного происхождения и растворенными нефтепродуктами. Определены концентрации, источники и пути распространения суммарной взвеси и загрязняющих веществ. Зафиксирован рост степени загрязнения заповедной акватории в течение двух последних лет.На основі аналізу даних оптичних спостережень у рамках комплексних океанографічних експедицій, проведених співробітниками ІнБЮМ НАНУ та МГІ НАНУ 22, 23 травня 2007 р. та 21, 22 липня 2009 р. у прибережних водах Чорного моря біля Карадазького заповідника, виконано оцінки забруднення розглянутої акваторії розчиненою органічною речовиною штучного походження та розчиненими нафтопродуктами. Визначено концентрації, джерела та шляхи поширення сумарної зваженої речовини та забруднюючих речовин. Зафіксовано зростання ступеню забруднення заповідної акваторії протягом двох останніх років.On the base of analysis of optical observations’ data within the framework of complex oceanographic expeditions, undertaken by employers of IBSS and MHI of National academy of sciences of Ukraine on 22, 23 May 2007 and 21, July 22 2009 in the coastal waters of the Black sea beside the Karadag reserve, estimations of water borne contaminations with dissolved organic material by man made birth and dissolved oil are executed. The concentrations, sources and the ways of the total suspended matter and polluting material spreading are defined. Increase in pollution percentage in waters of the reserve is fixed for two last years

SF-6D utility values for the better- and worse-seeing eye for health states based on the Snellen equivalent in patients with age-related macular degeneration

Objective: Economic evaluations in wet age-related macular degeneration (ARMD) is hampered as often utility values for solely one eye are used, mostly the better-seeing eye (BSE). Moreover, frequently chosen methods rely on patient values and/or disease specific measures, while economic evaluations prefer generic quality of life (QoL) measures based on societal preferences. The generic QoL utility instrument EQ-5D has shown to be insensitive for differences in visual acuity. The aim of this study was therefore to provide societal utility values, using the generic SF-6D, for health states acknowledging both BSE and worse-seeing eye (WSE). Methods: SF-6D utility values of 191 ARMD patients (≤65 years) with 153 follow-up measures at 1 year were used to fill health states defined by the combination of BSE and WSE using Snellen equivalents; no visual loss (≥20/40), mild-moderate (20/200) and severe (≤20/200). Results: QoL utilities were estimated for the SF-6D, ranging from 0.740 for ARMD patients without visual loss to 0.684 for patients with a combination of mild-moderate visual loss in their BSE and severe visual loss in their WSE. Conclusion: Societal utility values are provided for ARMD patients using the generic QoL instrument SF-6D for visual acuity health states based on both BSE and WSE. The range of the values is smaller than previous elicited utilities with the disease-specific VisQoL. Besides, the utility values are placed on a more realistic position on the utility scale, and SF-6D utility values avoid the problem associated with the interpretation of disease-specific utility values

The Leiden Ranking 2011/2012: Data collection, indicators, and interpretation

The Leiden Ranking 2011/2012 is a ranking of universities based on bibliometric indicators of publication output, citation impact, and scientific collaboration. The ranking includes 500 major universities from 41 different countries. This paper provides an extensive discussion of the Leiden Ranking 2011/2012. The ranking is compared with other global university rankings, in particular the Academic Ranking of World Universities (commonly known as the Shanghai Ranking) and the Times Higher Education World University Rankings. Also, a detailed description is offered of the data collection methodology of the Leiden Ranking 2011/2012 and of the indicators used in the ranking. Various innovations in the Leiden Ranking 2011/2012 are presented. These innovations include (1) an indicator based on counting a university's highly cited publications, (2) indicators based on fractional rather than full counting of collaborative publications, (3) the possibility of excluding non-English language publications, and (4) the use of stability intervals. Finally, some comments are made on the interpretation of the ranking, and a number of limitations of the ranking are pointed out

Six and eight weeks injection frequencies of bevacizumab are non-inferior to the current four weeks injection frequency for quality of life in neovascular age-related macular degeneration: a randomized controlled trial

Purpose: Patients with neovascular age-related macular degeneration (nARMD) will not deteriorate on visual acuity and retinal thickness when treated with bevacizumab injection frequencies of 6 or 8 weeks compared to 4 weeks. This study aimed to investigate this non-inferiority in quality of life (QoL). We hypothesized that less frequent bevacizumab injections are not inferior regarding patients reported QoL. Methods: Patients were randomized to bevacizumab every 4 (n = 64), 6 (n = 63), and 8 weeks (n = 64). Patients were at least 65 years old, have a best-corrected visual acuity of 20/200 to 20/20, no previous ARMD treatment and active leakage. Vision-related QoL questionnaire NEI VFQ-39 was used to assess QoL at baseline and after 1 year. General QoL questionnaire SF-36 was included for secondary analysis. Multilevel analyses were performed, correcting for age, gender and baseline. Results: The 6 (3.68; 95% CI − 0.63 to 8.00) and 8 (2.15; 95% CI − 2.26 to 6.56) weeks bevacizumab regimens resulted in non-inferior QoL differences compared to 4 weeks on the NEI VFQ-39. Also on the SF-36 the differences were well within the non-inferiority limits. Conclusion: Non-inferiority of the 6 and 8 weeks frequencies was demonstrated compared to 4 weeks on vision-related and general QoL in patients with nARMD. These results are in line with previously published results of lower frequency injections regarding visual acuity and central retinal thickness. Lower injection frequency may reduce burden, side effects, and treatment costs. In consideration of these results, 8 weeks frequency injections of intravitreal bevacizumab could be considered in patients with nARMD

On the correlation between bibliometric indicators and peer review: reply to Opthof and Leydesdorff

Opthof and Leydesdorff (Scientometrics, 2011) reanalyze data reported by Van Raan (Scientometrics 67(3):491–502, 2006) and conclude that there is no significant correlation between on the one hand average citation scores measured using the CPP/FCSm indicator and on the other hand the quality judgment of peers. We point out that Opthof and Leydesdorff draw their conclusions based on a very limited amount of data. We also criticize the statistical methodology used by Opthof and Leydesdorff. Using a larger amount of data and a more appropriate statistical methodology, we do find a significant correlation between the CPP/FCSm indicator and peer judgment

Quality of life of patients with chronic lymphocytic leukaemia in the Netherlands: results of a longitudinal multicentre study

Purpose: To describe the health-related quality of life (HRQoL) of an unselected population of patients with chronic lymphocytic leukaemia (CLL) including untreated patients. Methods: HRQoL was measured by the EORTC QLQ-C30 including the CLL16 module, EQ-5D, and VAS in an observational study over multiple years. All HRQoL measurements per patient were connected and analysed using area under the curve analysis over the entire study duration. The total patient group was compared with the general population, and three groups of CLL patients were described separately, i.e. patients without any active treatment (“watch and wait”), chlorambucil treatment only, and patients with other treatment(s). Results: HRQoL in the total group of CLL patients was compromised when compared with age- and gender-matched norm scores of the general population. CLL patients scored statistically worse on the VAS and utility score of the EQ-5D, all functioning scales of the EORTC QLQ-C30, and the symptoms of fatigue, dyspnoea, sleeping disturbance, appetite loss, and financial difficulties. In untreated patients, the HRQoL was slightly reduced. In all treatment stages, HRQoL was compromised considerably. Patients treated with chlorambucil only scored worse on the EORTC QLQ-C30 than patients who were treated with other treatments with regard to emotional functioning, cognitive functioning, bruises, uncomfortable stomach, and apathy. Conclusions: CLL patients differ most from the general population on role functioning, fatigue, concerns about future health, and having not enough energy. Once treatment is indicated, HRQoL becomes considerably compromised. This applies to all treatments, including chlorambucil, which is considered to be a mild treatment