For the economic measure, see. Cannot be combined with any other offer, discount, sale items, already reduced items, guest designer collaborations or select special collections. For Loyalty Members only: offer combinable with one Membership offer or reward. It might be simpler to divide citation counts by the number of authors before ordering the papers and obtaining the h-index, as originally suggested by Hirsch. Journal of the American Society for Information Science and Technology.
From July 2011 have provided an automatically-calculated h-index and within their own profile. Among 36 new inductees in the National Academy of Sciences in biological and biomedical sciences in 2005, the median h-index was 57. Journal of the American Society for Information Science and Technology. No adjustments on prior purchases. On average across the disciplines, a professor in the social sciences had an h-index about twice that of a lecturer or a senior lecturer, though the difference was the smallest in geography. The index was suggested in 2005 by , a physicist at , as a tool for determining ' relative quality and is sometimes called the Hirsch index or Hirsch number. The h-index is an that attempts to measure both the and of the of a or scholar.
The index is designed to improve upon simpler measures such as the total number of citations or publications. A successive Hirsch-type-index for institutions has also been devised. The h-index is intended to measure simultaneously the quality and quantity of scientific output. Then, we look for the last position in which f is greater than or equal to the position we call h this position. This method has not been readily adopted, perhaps because of its complexity. First we order the values of f from the largest to the lowest value. However, this finding was contradicted by another study by Hirsch.
It has been stated that citation behavior in general is affected by field-dependent factors, which may invalidate comparisons not only across disciplines but even within different fields of research of one discipline. During the period January 1, 2000 — February 28, 2010, a physicist had to receive 2073 citations to be among the most cited 1% of physicists in the world. Hirsch has demonstrated that h has high predictive value for whether a scientist has won honors like membership or the. The three h 2 metrics measure the relative area within a scientist's citation distribution in the low impact area, h 2 lower, the area captured by the h-index, h 2 center, and the area from publications with the highest visibility, h 2 upper. For example, if we have a researcher with 5 publications A, B, C, D, and E with 10, 8, 5, 4, and 3 citations, respectively, the h-index is equal to 4 because the 4th publication has 4 citations and the 5th has only 3.
Each database is likely to produce a different h for the same scholar, because of different coverage. Plus, don't miss out on all your Member rewards, birthday offer and special invites to events! Because only the most highly cited articles contribute to the h-index, its determination is a simpler process. When compared with a video creator's total view count, the h-index and g-index better capture both productivity and impact in a single metric. Yes, email me my member rewards, special invites, trend alerts and more. Your inbox is about to get a lot more stylish! The h-index has been applied to Internet Media, such as channels. Cannot be used for Gift Card purchase or shipping.
Scientists with high h 2 upper percentages are perfectionists, whereas scientists with high h 2 lower percentages are mass producers. Scopus has better coverage of conferences, but poor coverage of publications prior to 1996; Google Scholar has the best coverage of conferences and most journals though not all , but like Scopus has limited coverage of pre-1990 publications. It has been suggested that in order to deal with the sometimes wide variation in h for a single academic measured across the possible citation databases, one should assume false negatives in the databases are more problematic than false positives and take the maximum h measured for an academic. A value of about 18 could mean a full professorship, 15—20 could mean a fellowship in the , and 45 or higher could mean membership in the. However, later work has shown that since h-index is a cumulative measure, it contains intrinsic auto-correlation that led to significant overestimation of its predictability. In addition, specific databases, such as the database can automatically calculate the h-index for researchers working in.
. The index can also be applied to the productivity and impact of a as well as a group of scientists, such as a department or university or country. Of course this method does not deal with academic age bias. The exclusion of conference proceedings papers is a particular problem for scholars in , where conference proceedings are considered an important part of the literature. It was found that the distribution of the h-index, although it depends on the field, can be normalized by a simple rescaling factor. Therefore, these disciplines have lower citation thresholds in the Essential Science Indicators, with the lowest citation thresholds observed in social sciences 154 , computer science 149 , and multidisciplinary sciences 147.
A detailed study showed that the Web of Science has strong coverage of journal publications, but poor coverage of high impact conferences. For example, the Meho and Yang study found that Google Scholar identified 53% more citations than Web of Science and Scopus combined, but noted that because most of the additional citations reported by Google Scholar were from low-impact journals or conference proceedings, they did not significantly alter the relative ranking of the individuals. This article is about the index of scientific research impact. However, Hirsch noted that values of h will vary between different fields. Numbers are very different in social science disciplines: The Impact of the Social Sciences team at found that social scientists in the United Kingdom had lower average h-indices. The h-index serves as an alternative to more traditional journal metrics in the evaluation of the impact of the work of a particular researcher. One can be easily convinced that ranking in coauthorship networks should take into account both measures to generate a realistic and acceptable ranking.