Update on changes in ranking methodology

Times Higher Education (THE) have been preparing the ground for methodological changes in their world rankings. A recent article by Phil Baty  announced that the new world rankings scheduled for September 30 will not count the citations to 649 papers, mainly in particle physics, with more than 1000 authors.

This is perhaps the best that is technically and/or commercially feasible at this moment but it is far from satisfactory. Some of these publications are dealing with the most basic questions about the nature of physical reality and it is a serious distortion not to include them in the ranking methodology. There have been complaints about this. Pavel Krokovny's comment was noted in a previous post while Mete Yeyisoglu argues that:

"Fractional counting is the ultimate solution. I wish you could have worked it out to use fractional counting for the 2015-16 rankings.
The current interim approach you came up with is objectionable.
Why 1,000 authors? How was the limit set? What about 999 authored-articles?
Although the institution I work for will probably benefit from this interim approach, I think you should have kept the same old methodology until you come up with an ultimate solution.
This year's interim fluctuation will adversely affect the image of university rankings."

Baty provides a reasonable answer to the question why the cut-off point is 1,000 authors.

But there is a fundamental issue developing here that goes beyond ranking procedure. The concept of authorship of a philosophy paper written entirely by a single person or a sociological study from a small research team is very different from that of the huge multi-national capital and labour intensive publications in which the number of collaborating institutions exceeds the number of  paragraphs and there are more authors than sentences.

Fractional counting does seem to be the only fair and sensible way forward and it is now apparently on THE's agenda although they have still not committed themselves.

The objection could be raised that while the current THE system gives a huge reward to even the least significant contributing institution, fractional counting would give major research universities insufficient credit for their role in important research projects.

A long term solution might be to draw a distinction between the contributors to and the authors of the mega papers. For most publications there would be no need to draw such a distinction but for those with some sort of input from dozens, hundreds or thousands of people it might be feasible for to allot half the credit to all those who had anything to do with the project and the other half to those who meet the standard criteria of authorship. There would no doubt be a lot of politicking about who gets the credit but that would be nothing new.

Duncan Ross, the new Data and Analytics Director at THE, seems to be thinking along these lines.

"In the longer term there are one technical and one structural approach that would be viable.  The technical approach is to use a fractional counting approach (2932 authors? Well you each get 0.034% of the credit).  The structural approach is more of a long term solution: to persuade the academic community to adopt metadata that adequately explains the relationship of individuals to the paper that they are ‘authoring’.  Unfortunately I’m not holding my breath on that one."

The counting of citations to mega papers is not the only problem with the THE citations indicator. Another is the practice of giving a boost to universities in underperforming countries. Another item by Phil Baty quotes this justification from Thomson Reuters, THE's former data partner.

“The concept of the regional modification is to overcome the differences between publication and citation behaviour between different countries and regions. For example some regions will have English as their primary language and all the publications will be in English, this will give them an advantage over a region that publishes some of its papers in other languages (because non-English publications will have a limited audience of readers and therefore a limited ability to be cited). There are also factors to consider such as the size of the research network in that region, the ability of its researchers and academics to network at conferences and the local research, evaluation and funding policies that may influence publishing practice.”

THE now appear to agree that this is indefensible in the long run and hope that a more inclusive academic survey and the shift to Scopus, with broader coverage than the Web of Science, will lead to this adjustment being phased out.

It is a bit odd that TR and THE should have introduced income, in three separate indicators, and international outlook, in another three, as markers of excellence, but then included a regional modification to compensate for limited funding and international contacts.

THE are to be congratulated for having put fractional counting and phasing out the regional modification on their agenda. Let's hope it doesn't take too long.

While we are on the topic, there are some more things about the citation indicator to think about . First, to repeat a couple of points mentioned in the earlier post.

• Reducing the number of fields or doing away with normalisation by year of citation. The more boxes into which any given citation can be dropped the greater the chance of statistical anomalies when a cluster of citations meets a low world average of citations for that particular year of citations, year of publication and field (300 in Scopus?)

• Reducing the weighting for this indicator. Perhaps citations per paper normalized by field is a useful instrument for comparing the quality of research of MIT, Caltech, Harvard and the like but it might be of little value when comparing the research performance of Panjab University and IIT Bombay or Istanbul University and  Bogazici.

Some other things THE could think about.

• Adding a measure of overall research impact, perhaps simply by counting citations. At the very least stop calling field- and year- normalised regionally modified citations per paper a measure of research impact. Call it research quality or something like that.

• Doing something about secondary affiliations. So far this seems to have been a problem mainly  for the Highly Cited Researchers indicator in the Shanghai ARWU but it may not be very long before more universities realise  that a few million dollars for adjunct faculty could have a disproportion impact on publication and citation counts.

• Also, perhaps THE should consider excluding self-citations (or even citations within the same institution although that would obviously be technically difficult). Self-citation caused a problem in 2010 when Dr El Naschie's diligent citation of himself and a few friends lifted Alexandria University to fourth place in the world for research impact. Something similar might happen again now that THE are using a larger and less selective database.

The Richest University in China ...

   ...   is Tsinghua University but Zhejiang, Peking and Shanghai Jiao Tong Universities appear to be more productive, as measured by the Publications indicator in the Shanghai rankings.

China Daily has just published a list of the top ten universities in China ranked according to annual income as reported to the Ministry of Education. Here they are with the Publications score (papers in the Science Citation Index and the Social Science Citation Index in 2014) in brackets.


1.     Tsinghua University 17.56 billion yuan (63.8)
2.     Zhejiang University 15.64 billion yuan  (68.5)
3.     Peking University 12.85 billion yuan      (64)
4.     Shanghai Jiao Tong University 11.89 billion yuan   (68.5)
5.     Fudan University 7.71 billion yuan (56.1)
6.     Wuhan University 6.83 billion yuan (45.8)
7.     Jilin University 6.82 billion yuan  (50.7)
8.     Huazhong University of Science and Technology 6.81 billion yuan  (53.1)
9.     Sun Yat-sen University 6.69 billion yuan (54.9)
10.   Sichuan University 6.58 billion yuan    (54.2).

Not fair to call papers freaky

A comment by Pavel Krokovny of Heidelberg University about THE's proposal to exclude papers with 1,000+ authors from their citations indicator in the World University Rankings.

"It is true that all 3k+ authors do not draft the paper together, on the contrary, only a small part of them are involved in this very final step of a giant research work leading to a sound result. It is as well true that making the research performed public and disseminating the knowledge obtained is a crucial step of the whole project. 
But what you probably missed is that this key stage would not be possible at all without a unique setup which was built and operated by profoundly more physicists and engineers than those who processed raw data and wrote a paper. Without that "hidden part of the iceberg" there would be no results at all. And it would be completely wrong to assume that the authors who did the data analysis and wrote the paper should be given the highest credit in the paper. It is very specific for the experimental HEP field that has gone far beyond the situation that was common still in the first half of 20th century when one scientist or a small group of them might produce some interesting results. The "insignificant" right tail in your distribution of papers on number of coauthors contains the hot part of the modern physics with high impact results topped by the discovery of Higgs-boson. And in your next rankings you are going to dishonour those universities that contributed to this discovery."

and

"the point is that frequent fluctuations of the ranking methodology might damage the credibility of the THE. Certainly, I do not imply here large and well-esteemed universities like Harvard or MIT. I believe their high rankings positions not to be affected by nearly any reasonable changes in the methodology. However, the highest attention to the rankings is attracted from numerous ordinary institutions across the world and their potential applicants and employees. In my opinion, these are the most concerned customers of the THE product. As I already pointed out above, it's very questionable whether participation in large HEP experiments (or genome studies) should be considered "unfair" for those institutions."

Changes in Ranking Methodology

This year and next the international university rankings appear to be set for more volatility with unusually large upward and downward movement, partly as a result of changes to the methodology for counting citations in the QS and THE rankings.

ARWU

The global ranking season kicked off last week with the publication of the latest edition of the Academic Ranking of World Universities from the ShanghaiRanking Consultancy (SRC), which I hope to discuss in detail in a little while. These rankings are rather dull and boring, which is exactly what they should be. Harvard is, as always, number one for all but one of the indicators. Oxford has slipped from joint ninth to tenth place. Warwick has leaped into the top 100 by virtue of a Fields medal. At the foot of the table there are new contenders from France, Korea and Iran.

Since they began in 2003 the Shanghai rankings have been characterised by a  generally stable methodology. In 2012, however, they had to deal with the recruitment of a large and unprecedented number of adjunct faculty by King Abdulaziz University. Previously SRC had simply divided the credit for the Highly Cited Researchers indicator equally between all institutions listed as affiliations. In 2012 and 2013 they wrote to all highly cited researchers with joint affiliations and thus determined the division of credit between primary and secondary affiliations. Then, in 2014 and this year they combined the old Thomson Reuters list, first issued in 2001, and the new one, issued in 2014, and excluded all secondary affiliations in the new list.

The result was that in 2014 the rankings showed an unusual degree of volatility although this year things are a lot more stable. My understanding is that Shanghai will move to counting only the new list next year, again without secondary affiliations, so there should be a lot of interesting changes then. It looks as though Stanford, Princeton, University of Wisconsin -- Madison, and Kyoto University will suffer because of the change while University of California Santa Cruz, Rice University, University of Exeter and University of Wollongong. will benefit.

While SRC has efficiently dealt with the issue of secondary affiliation with regard to its Highly Cited indicator, the issue has now resurfaced in the unusual high scores achieved  by King Abdulaziz University for publications largely because of its adjunct faculty. Expect more discussion over the next year or so. It would seem sensible for SRC to think about a five or ten year period rather than one year for their Publications indicator and academic publishers, the media and rankers in general may need to give some thought to the proliferation of secondary affiliations.


QS

On July 27 Quacquarelli Symonds (QS) announced that for 18 months they had been thinking about normalising the counting of citations across five broad subject areas. They observed that a typical institution would receive about half of its citations from the life sciences and medicine, over a quarter from the natural sciences but just 1% from the arts and humanities.

In their forthcoming rankings QS will assign a 20% weighting for citations to each of the five subject areas something, according to Ben Sowter Research Director at QS, that they have been doing for the academic opinion survey.

It would seem then that there are likely to be some big rises and big falls this September. I would guess that places strong in humanities, social sciences and engineering like LSE, New York University and Nanyang Technological University may go up and some of the large US state universities and Russian institutions may go down. That's a guess because it is difficult to tell what happens with the academic and employer surveys.

QS have also made an attempt to deal with the issue of hugely cited papers with hundreds, even thousands of "authors" -- contributors would be a better term -- mainly in physics, medicine and genetics. Their approach is to exclude all papers with more than 10 contributing institutions, that is 0.34% of all publications in the database.

This is rather disappointing. Papers with huge numbers of authors and citations obviously do have distorting effects but they have often dealt with fundamental and important issues. To exclude them altogether is to ignore a very significant body of research.

The obvious solution to the problem of multi-contributor papers is fractional counting, dividing the number of citations by the number of contributors or contributing institutions. QS claim that to do so would discourage collaboration, which does not sound very plausible.

In addition, QS will likely extend the life of  survey responses from three to five years. That could make the rankings more stable by smoothing out annual fluctuations in survey responses and reduce the volatility caused by the proposed changes in the counting of citations.

The shift to a moderate version of field normalisation is helpful as it will reduce the undue privilege given to medical research, without falling into the huge problems that result from using too many categories. It is unfortunate, however, that QS have not taken the plunge into fractional counting. One suspects that technical problems and financial considerations might be as significant as the altruistic desire not to discourage collaboration.

After a resorting in September the QS rankings are likely to become a bit more stable and and credible but their most serious problem, the structure, validity and excessive weighting of the academic survey, has still not been addressed.

THE

Meanwhile, Times Higher Education (THE) has also been grappling with the issue of authorship inflation. Phil Baty has announced that this year 649 papers with over 1,000 authors will be excluded from their calculation of citations because " we consider them to be so freakish that they have the potential to distort the global scientific landscape".

But it is not the papers that do the distorting. It is  methodology.  THE and their former data partners Thomson Reuters, like QS, have avoided  fractional counting (except for a small experimental African ranking) and so every one of those hundreds or thousands of authors gets full credit for the hundreds  or thousands of citations. This has given places like Tokyo Metropolitan University, Scuola Normale Superiore Pisa, Universite Cadi Ayyad in Morocco and Bogazici University in Turkey remarkably high scores  for Citations: Research Impact, much higher than their scores for the bundled research indicators.

THE have decided to simply exclude 649 papers, 0r 0.006% of the total from their calculations for the world rankings. This seems a lot less than QS. Again, this is a rather crude measure. Many of the "freaks" are major contributions to advanced research and deserve to be acknowledged by the rankings in some way. 

THE did use fractional counting in their recent experimental ranking of African universities and Baty indicates that they are considering doing so in the future.

It would be a big step forward for THE if they introduce fractional counting of citations. But they should not stop there. There are other bugs in the citations indicator that ought to be fixed.

First, it does not at present measure what it is supposed to measure. It does not measure a university's overall research impact. At best, it is a measure of the average quality of research papers no matter how few (above a certain threshold) they are.

Second, the "regional modification", which divides the university citation impact score by the square root of the the score of the country where the university is located, is another source  of distortion. It gives a bonus to universities simply for being located in  underperforming countries. THE or TR have justified the modification by suggesting that some universities deserve compensation because they lack funding or networking opportunities. Perhaps they do, but this can still lead to serious anomalies.

Thirdly, THE need to consider whether they should assign citations to so many fields since this increases the distortions that can arise when there is a highly cited paper in a normally lowly cited field.

Fourthly, should they assign a thirty per cent weighting to an indicator that may be useful for distinguishing between the likes of MIT and Caltech but may be of little relevance for the universities that are now signing up for the world rankings?