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Twitter's science stars, the sequel
Martyn Green

Twitter's science stars, the sequel

We listed. You tweeted (often in outrage). We listened (mostly). And now we’re doubling down on our recent list of Twitter’s 50 most popular researchers with a revision that names 100 of the most followed scientists on the social media platform. (See below for that list, or download our updated spreadsheet, which marks the additions in red.)

The first list—in case you missed it last month—was part of a story examining the use of Twitter by scientists, prompted by the furor that had erupted over the so-called Kardashian Index (K-index). This metric, whose inventor says he meant it in fun, compared a researcher’s number of Twitter followers with the number of citations to his or her academic papers. Our story explored why some highly respected scientists had embraced tweeting, but we also made a stab at compiling a list of the most followed researchers on Twitter, which online we dared to headline “The top 50 science stars of Twitter.”

Well, make a list of the “best,” “worst,” or “top” and you’re asking for trouble. Many, including biologist Jonathan Eisen, who was one of our original top 50 and who has argued that tweeting helps his career, took to Twitter to question why we conferred stardom based on a simple ranking of follower number, with some calling that a meaningless popularity contest. Others suggested alternative ways to measure the impact a scientist has on Twitter, among them retweets, direct mentions, and Klout Score. Euan Adie of Altmetric probably took the most serious look at an influence-based ranking of science-themed Twitter accounts with this blog post on the “The Real Science Stars of Twitter.”

And then there were the many Twitter stars we failed to spot. We had clear criteria and an explicit methodology (repeated below the revised list), but the original list had numerous and notable omissions—sorry, Francis Collins (@NIHDirector) and Sylvia Earle (@SylviaEarle), for example! And kudos to Noah Gray (@NoahWG) who noticed that rock star (and Ph.D. astrophysicist) Brian May fit our criteria—he’s now #12 on our new list.

Some decried the lack of scientists of color or female scientists on our list—just four women made the top 50, for example—and noted that our search strategy, which started with a handful of Twitter celebrity scientists and looked at who they followed, likely biased our discoveries toward white males. In our story, we took the identified gender disparity at face value and explored some reasons why women might avoid Twitter or be less followed. But a slew of women scientists are clearly popular on Twitter—the hashtag #womentweetsciencetoo quickly collected an impressive list, most if not all noted in this blog post, and we’ve added those with the most followers. We also reviewed several other public Twitter lists, including the lengthy BLACKandSTEM created by Stephani Page (@ThePurplePage), for other omissions.

In the end, we added anyone suggested to Science who met our criteria and who had more than 11,600 followers, enough to qualify for 50th position in the original list. We also opened the list to economists, as their field has its own Nobel Prize and is represented by one of the sections of AAAS (the publisher of Science). The result: Our list more than doubled in size and now includes a large number of newly added women. But few women cracked the revised list’s top 50—just seven—which now has a threshold of more than 33,000 followers, versus 11,600 in the original list. The newly added economists, 18 in total, are partly to blame; they are highly followed on Twitter and are predominantly male. (We list the top 100 below, but our spreadsheet includes additional suggestions that pushed the total beyond that.)

A note to doctors: Our original list included several highly cited physician researchers who we didn’t notice bypassed our Ph.D. requirement. We’ve kept the originals on the new list but declined suggestions that we add other M.D.-only physicians—perhaps they can petition a medical journal to create their own list of Twitter stars? Other than that, we’ve made our best effort to include everyone who qualifies.

And with that, here’s 100 of the most followed scientists on Twitter …

  • Neil deGrasse Tyson

    1. Neil deGrasse Tyson, Astrophysicist
    2,460,000 followers @neiltyson
    Citations: 159 K-index: 11,220
    Total number of tweets: 4,001
    Hayden Planetarium, United States

  • Brian Cox

    2. Brian Cox, Physicist
    1,450,000 followers @ProfBrianCox
    Citations: 33,531 K-index: 1,193
    Total number of tweets: 10,400
    University of Manchester, United Kingdom

  • Mike Massimino

    3. Mike Massimino, Mechanical engineer/astronaut
    1,290,000 followers @Astro_Mike
    Citations: 5,459 K-index: 1,898
    Total number of tweets: 1,556
    NASA, United States

  • Paul Krugman+

    4. Paul Krugman+, Economist
    1,250,000 followers @NYTimesKrugman
    Citations: 139,845 K-index: 651
    Total number of tweets: 5,754
    Princeton University, United States

  • Richard Dawkins

    5. Richard Dawkins, Biologist
    1,030,000 followers @RichardDawkins
    Citations: 49,631 K-index: 748
    Total number of tweets: 19,300
    University of Oxford, United Kingdom

  • Ben Goldacre

    6. Ben Goldacre, Physician
    345,000 followers @bengoldacre
    Citations: 1,086 K-index: 851
    Total number of tweets: 47,400
    London School of Hygiene & Tropical Medicine, United Kingdom

  • AndrÌ© Kuipers

    7. Andr̩ Kuipers, Physician/astronaut
    332,000 followers @astro_andre
    Citations: 6,344 K-index: 465
    Total number of tweets: 1,749
    European Space Agency

  • Phil Plait

    8. Phil Plait, Astronomer
    325,000 followers @BadAstronomer
    Citations: 254 K-index: 1,276
    Total number of tweets: 47,300
    Bad Astronomy, United States

  • Michio Kaku

    9. Michio Kaku, Theoretical physicist
    315,000 followers @michiokaku
    Citations: 5,281 K-index: 468
    Total number of tweets: 1,139
    The City College of New York, United States

  • Nouriel Roubini

    10. Nouriel Roubini, Economist
    313,000 followers @nouriel
    Citations: 17,484 K-index: 317
    Total number of tweets: 10,200
    New York University, United States

  • Sam Harris

    11. Sam Harris, Neuroscientist
    231,000 followers @SamHarrisOrg
    Citations: 2,416 K-index: 441
    Total number of tweets: 2,725
    Project Reason, United States

  • Brian May

    12. Brian May, Astrophysicist/guitarist
    206,000 followers @DrBrianMay
    Citations: 34 K-index: 1,539
    Total number of tweets: 8,002
    Imperial College London, United Kingdom (& Queen)

  • Hans Rosling

    13. Hans Rosling, Global health scientist
    185,000 followers @HansRosling
    Citations: 1,703 K-index: 395
    Total number of tweets: 2,733
    Karolinska Institute, Sweden

  • Tim Berners-Lee

    14. Tim Berners-Lee, Computer scientist
    183,000 followers @timberners_lee
    Citations: 51,204 K-index: 132
    Total number of tweets: 556
    Massachusetts Institute of Technology, United States

  • Richard Florida

    15. Richard Florida, Economist
    177,000 followers @Richard_Florida
    Citations: 36,537 K-index: 142
    Total number of tweets: 45,800
    University of Toronto, Canada

  • Nobuo Ikeda

    16. Nobuo Ikeda, Economist
    170,000 followers @ikedanob
    Citations: 2,026 K-index: 343
    Total number of tweets: 47,500
    Agora Institute, Japan

  • Jeffrey D. Sachs

    17. Jeffrey D. Sachs, Economist
    164,000 followers @JeffDSachs
    Citations: 112 K-index: 837
    Total number of tweets: 5,865
    Columbia University, United States

  • P. Z. Myers

    18. P. Z. Myers, Biologist
    156,000 followers @pzmyers
    Citations: 1,364 K-index: 358
    Total number of tweets: 25,700
    University of Minnesota, Morris, United States

  • Alexander Gerst

    19. Alexander Gerst, Astronaut
    154,000 followers @Astro_Alex
    Citations: 163 K-index: 697
    Total number of tweets: 2,250
    European Space Agency

  • Steven Pinker

    20. Steven Pinker, Cognitive scientist
    145,000 followers @sapinker
    Citations: 49,933 K-index: 105
    Total number of tweets: 1,674
    Harvard University, United States

  • Richard Wiseman

    21. Richard Wiseman, Psychologist
    135,000 followers @RichardWiseman
    Citations: 4,687 K-index: 209
    Total number of tweets: 22,600
    University of Hertfordshire, United Kingdom

  • Ryugo Hayano

    22. Ryugo Hayano, Nuclear physicist
    124,000 followers @hayano
    Citations: 956 K-index: 319
    Total number of tweets: 56,500
    University of Tokyo, Japan

  • Toshiyuki Masui

    23. Toshiyuki Masui, Computer scientist
    122,000 followers @masui
    Citations: 3,338 K-index: 210
    Total number of tweets: 29,900
    Keio University, Japan

  • Marion Nestle

    24. Marion Nestle, Nutritionist
    118,000 followers @marionnestle
    Citations: 7,176 K-index: 159
    Total number of tweets: 3,944
    New York University, United States

  • Dambisa Moyo

    25. Dambisa Moyo, Economist
    104,000 followers @dambisamoyo
    Citations: 1,612 K-index: 226
    Total number of tweets: 2,084
    Barclays, United Kingdom

  • Lawrence M. Krauss

    26. Lawrence M. Krauss, Theoretical physicist
    104,000 followers @LKrauss1
    Citations: 10,206 K-index: 125
    Total number of tweets: 1,632
    Arizona State University, United States

  • Danah Boyd

    27. Danah Boyd, Social media scientist
    103,000 followers @zephoria
    Citations: 16,274 K-index: 107
    Total number of tweets: 4,755
    Microsoft Research, United States

  • Karen Nyberg

    28. Karen Nyberg, Astronaut
    103,000 followers @AstroKarenN
    Citations: 87 K-index: 570
    Total number of tweets: 856
    NASA, United States

  • Atul Gawande

    29. Atul Gawande, Surgeon/public health scientist
    98,100 followers @Atul_Gawande
    Citations: 14,106 K-index: 107
    Total number of tweets: 2,139
    Harvard University, United States

  • Nassim Taleb

    30. Nassim Taleb, Statistician
    79,100 followers @nntaleb
    Citations: 6,523 K-index: 110
    Total number of tweets: 427
    New York University, United States

  • Oliver Sacks

    31. Oliver Sacks, Neurologist
    77,800 followers @OliverSacks
    Citations: 13,883 K-index: 85
    Total number of tweets: 754
    New York University, United States

  • Dan Ariely*

    32. Dan Ariely*, Psychologist/behavioral economist
    74,300 followers @danariely
    Citations: 16,766 K-index: 76
    Total number of tweets: 1,098
    Duke University, United States

  • Alice Roberts

    33. Alice Roberts, Clinical anatomist
    68,900 followers @DrAliceRoberts
    Citations: 1,850 K-index: 143
    Total number of tweets: 8,333
    University of Birmingham, United Kingdom

  • Freek Vonk

    34. Freek Vonk, Biologist
    68,400 followers @freekvonk
    Citations: 653 K-index: 199
    Total number of tweets: 6,523
    Naturalis Biodiversity Center, the Netherlands

  • William Easterly*

    35. William Easterly*, Economist
    63,200 followers @bill_easterly
    Citations: 41,935 K-index: 48
    Total number of tweets: 9,817
    New York University, United States

  • Justin Wolfers

    36. Justin Wolfers, Economist
    62,600 followers @JustinWolfers
    Citations: 9,314 K-index: 78
    Total number of tweets: 16,600
    University of Michigan, United States

  • Jim Al-Khalili

    37. Jim Al-Khalili, Theoretical physicist
    60,900 followers @jimalkhalili
    Citations: 2,052 K-index: 123
    Total number of tweets: 9,165
    University of Surrey, United Kingdom

  • Tim Noakes

    38. Tim Noakes, Sports scientist
    48,200 followers @ProfTimNoakes
    Citations: 1,306 K-index: 112
    Total number of tweets: 13,100
    University of Cape Town, South Africa

  • Austan Goolsbee

    39. Austan Goolsbee, Economist
    47,700 followers @Austan_Goolsbee
    Citations: 4,924 K-index: 73
    Total number of tweets: 2,624
    University of Chicago, United States

  • Eric Topol*

    40. Eric Topol*, Geneticist
    46,100 followers @EricTopol
    Citations: 152,453 K-index: 23
    Total number of tweets: 5,035
    The Scripps Research Institute, United States

  • Kaushik Basu

    41. Kaushik Basu, Economist
    45,800 followers @kaushikcbasu
    Citations: 11,476 K-index: 53
    Total number of tweets: 2,089
    World Bank

  • Tyler Cowen

    42. Tyler Cowen, Economist
    45,600 followers @tylercowen
    Citations: 4,388 K-index: 72
    Total number of tweets: 11,200
    George Mason University, United States

  • Dani Rodrik

    43. Dani Rodrik, Economist
    45,500 followers @rodrikdani
    Citations: 67,680 K-index: 30
    Total number of tweets: 10,500
    Institute for Advanced Study, United States

  • Brian Greene

    44. Brian Greene, Theoretical physicist
    39,900 followers @bgreene
    Citations: 11,133 K-index: 47
    Total number of tweets: 197
    Columbia University, United States

  • Melanie Greenberg

    45. Melanie Greenberg, Clinical psychologist
    37,600 followers @DrMelanieG
    Citations: 1,924 K-index: 77
    Total number of tweets: 82,300
    Private practice, United States

  • Joseph E. Stiglitz+

    46. Joseph E. Stiglitz+, Economist
    35,200 followers @JosephEStiglitz
    Citations: 169,474 K-index: 17
    Total number of tweets: 166
    Columbia University, United States

  • Sylvia Earle

    47. Sylvia Earle, Marine biologist/oceanographer
    35,100 followers @SylviaEarle
    Citations: 890 K-index: 92
    Total number of tweets: 1,625
    National Geographic, United States

  • Marcus du Sautoy

    48. Marcus du Sautoy, Mathematician
    34,800 followers @MarcusduSautoy
    Citations: 1,472 K-index: 78
    Total number of tweets: 3,572
    University of Oxford, United Kingdom

  • Francis Collins*

    49. Francis Collins*, Physician-geneticist
    34,200 followers @NIHDirector
    Citations: 124,119 K-index: 19
    Total number of tweets: 531
    National Institutes of Health, United States

  • Sean Carroll

    50. Sean Carroll, Theoretical physicist
    33,800 followers @seanmcarroll
    Citations: 14,373 K-index: 36
    Total number of tweets: 7,352
    California Institute of Technology, United States

  • Robert Winston

    51. Robert Winston, Fertility scientist
    32,200 followers @ProfRWinston
    Citations: 7,359 K-index: 43
    Total number of tweets: 446
    Imperial College London, United Kingdom

  • Jared Bernstein

    52. Jared Bernstein, Economist
    31,200 followers @econjared
    Citations: 5,310 K-index: 46
    Total number of tweets: 3,288
    Center on Budget and Policy Priorities, United States

  • Bruce Betts

    53. Bruce Betts, Planetary scientist
    29,000 followers @RandomSpaceFact
    Citations: 91 K-index: 158
    Total number of tweets: 1,666
    The Planetary Society, United States

  • Carolyn Porco

    54. Carolyn Porco, Planetary scientist
    26,700 followers @carolynporco
    Citations: 2,741 K-index: 49
    Total number of tweets: 12,900
    Space Science Institute, United States

  • Adam Grant

    55. Adam Grant, Organizational psychologist
    26,500 followers @AdamMGrant
    Citations: 4,317 K-index: 42
    Total number of tweets: 1,452
    The Wharton School, University of Pennsylvania, United States

  • Sebastian Thrun+

    56. Sebastian Thrun+, Computer scientist
    25,800 followers @SebastianThrun
    Citations: 54,907 K-index: 18
    Total number of tweets: 187
    Stanford University, United States

  • Jonathan Eisen*

    57. Jonathan Eisen*, Biologist
    25,600 followers @phylogenomics
    Citations: 41,804 K-index: 20
    Total number of tweets: 47,237
    University of California, Davis, United States

  • David

    58. David "Danny" Blanchflower, Economist
    24,600 followers @D_Blanchflower
    Citations: 16,960 K-index: 25
    Total number of tweets: 42,094
    Dartmouth College, United States

  • J. Craig Venter

    59. J. Craig Venter, Genomicist
    24,200 followers @JCVenter
    Citations: 75,931 K-index: 15
    Total number of tweets: 373
    J. Craig Venter Institute, United States

  • Vaughan Bell

    60. Vaughan Bell, Neuroscientist
    24,200 followers @vaughanbell
    Citations: 836 K-index: 65
    Total number of tweets: 10,997
    King's College London, United Kingdom

  • Robert Simpson

    61. Robert Simpson, Astronomer
    22,300 followers @orbitingfrog
    Citations: 7,968 K-index: 29
    Total number of tweets: 11,600
    University of Oxford, United Kingdom

  • Michael E. Mann*

    62. Michael E. Mann*, Meteorologist
    21,700 followers @MichaelEMann
    Citations: 15,214 K-index: 23
    Total number of tweets: 20,500
    Pennsylvania State University, United States

  • Dean Baker

    63. Dean Baker, Economist
    21,300 followers @DeanBaker13
    Citations: 10,758 K-index: 25
    Total number of tweets: 7,285
    Center for Economic and Policy Research, United States

  • Amy Cuddy

    64. Amy Cuddy, Social psychologist
    21,300 followers @amyjccuddy
    Citations: 6,175 K-index: 30
    Total number of tweets: 4,017
    Harvard University, United States

  • Mark Thoma

    65. Mark Thoma, Economist
    20,800 followers @MarkThoma
    Citations: 799 K-index: 57
    Total number of tweets: 42,100
    University of Oregon, United States

  • David Eagleman

    66. David Eagleman, Neuroscientist
    20,100 followers @davideagleman
    Citations: 2,768 K-index: 37
    Total number of tweets: 1,482
    Baylor College of Medicine, United States

  • Jerry Coyne

    67. Jerry Coyne, Biologist
    20,100 followers @Evolutionistrue
    Citations: 16,817 K-index: 21
    Total number of tweets: 7,380
    University of Chicago, United States

  • Noah Smith

    68. Noah Smith, Economist
    19,900 followers @Noahpinion
    Citations: 5,483 K-index: 29
    Total number of tweets: 34,800
    Stony Brook University, United States

  • Gary King*

    69. Gary King*, Political scientist
    19,800 followers @kinggary
    Citations: 36,858 K-index: 16
    Total number of tweets: 3,104
    Harvard University, United States

  • Sinan Aral

    70. Sinan Aral, Information sciences
    19,100 followers @sinanaral
    Citations: 3,306 K-index: 33
    Total number of tweets: 5,696
    Massachusetts Institute of Technology, United States

  • Mike Brown

    71. Mike Brown, Astronomer
    18,700 followers @plutokiller
    Citations: 7,870 K-index: 24
    Total number of tweets: 9,888
    California Institute of Technology, United States

  • Pamela L. Gay

    72. Pamela L. Gay, Astronomer
    18,400 followers @starstryder
    Citations: 248 K-index: 73
    Total number of tweets: 12,900
    Southern Illinois University, Edwardsville, United States

  • Jean Francois GariÌ©py

    73. Jean Francois Gari̩py, Neuroscientist
    18,100 followers @JFGariepy
    Citations: 187 K-index: 78
    Total number of tweets: 3,247
    Duke University, United States

  • Robert Metcalfe

    74. Robert Metcalfe, Computer scientist
    16,600 followers @BobMetcalfe
    Citations: 5,251 K-index: 25
    Total number of tweets: 16,300
    University of Texas, Austin, United States

  • Daniel Gilbert+

    75. Daniel Gilbert+, Psychologist
    16,200 followers @DanTGilbert
    Citations: 28,576 K-index: 14
    Total number of tweets: 1,301
    Harvard University, United States

  • Daniel Levitin

    76. Daniel Levitin, Neuroscientist
    15,800 followers @danlevitin
    Citations: 5,852 K-index: 23
    Total number of tweets: 3,040
    McGill University, Canada

  • Paul Bloom

    77. Paul Bloom, Psychologist
    15,700 followers @paulbloomatyale
    Citations: 14,369 K-index: 17
    Total number of tweets: 2,009
    Yale University, United States

  • Andrew Maynard

    78. Andrew Maynard, Environmental health scientist
    15,600 followers @2020science
    Citations: 10,543 K-index: 19
    Total number of tweets: 16,300
    University of Michigan Risk Science Center, United States

  • David Grinspoon

    79. David Grinspoon, Astrobiologist
    15,600 followers @DrFunkySpoon
    Citations: 2,914 K-index: 28
    Total number of tweets: 9,736
    Library of Congress, United States

  • Pascal Wallisch

    80. Pascal Wallisch, Neuroscientist
    15,400 followers @Pascallisch
    Citations: 85 K-index: 86
    Total number of tweets: 1,118
    New York University, United States

  • Dorothy Bishop

    81. Dorothy Bishop, Neuropsychologist
    15,400 followers @deevybee
    Citations: 28,848 K-index: 13
    Total number of tweets: 14,800
    University of Oxford, United Kingdom

  • John Lennox

    82. John Lennox, Mathematician
    15,400 followers @ProfJohnLennox
    Citations: 2,443 K-index: 29
    Total number of tweets: 71
    University of Oxford, United Kingdom

  • Sarah-Jayne Blakemore

    83. Sarah-Jayne Blakemore, Cognitive Neuroscientist
    15,200 followers @sjblakemore
    Citations: 12,819 K-index: 17
    Total number of tweets: 5,661
    University College London, United Kingdom

  • Matt Lieberman

    84. Matt Lieberman, Neuroscientist
    15,000 followers @social_brains
    Citations: 13,099 K-index: 17
    Total number of tweets: 3,128
    University of California, Los Angeles, United States

  • Seth Shostak

    85. Seth Shostak, Astronomer
    14,800 followers @SethShostak
    Citations: 427 K-index: 49
    Total number of tweets: 299
    SETI Institute, United States

  • Amy Mainzer

    86. Amy Mainzer, Astronomer
    14,700 followers @AmyMainzer
    Citations: 1,516 K-index: 33
    Total number of tweets: 2,295
    Jet Propulsion Laboratory, United States

  • Katie Mack

    87. Katie Mack, Astrophysicist
    14,600 followers @AstroKatie
    Citations: 364 K-index: 51
    Total number of tweets: 44,300
    University of Melbourne, Australia

  • Daniel MacArthur

    88. Daniel MacArthur, Genomicist
    14,500 followers @dgmacarthur
    Citations: 7,208 K-index: 20
    Total number of tweets: 15,800
    Harvard Medical School, United States

  • John Allen Paulos

    89. John Allen Paulos, Mathematician
    14,400 followers @JohnAllenPaulos
    Citations: 1,494 K-index: 32
    Total number of tweets: 4,167
    Temple University, United States

  • Ves Dimov

    90. Ves Dimov, Immunologist
    14,300 followers @DrVes
    Citations: 224 K-index: 58
    Total number of tweets: 32,300
    University of Chicago, United States

  • Simon Baron-Cohen

    91. Simon Baron-Cohen, Psychopathologist
    14,100 followers @sbaroncohen
    Citations: 85,757 K-index: 9
    Total number of tweets: 121
    University of Cambridge, United Kingdom

  • Catherine Qualtrough

    92. Catherine Qualtrough, Astrophysicist
    13,700 followers @CatherineQ
    Citations: 187 K-index: 59
    Total number of tweets: 107,000
    University of North Carolina, Charlotte, United States

  • Deborah Berebichez

    93. Deborah Berebichez, Physicist
    13,100 followers @debbiebere
    Citations: 12 K-index: 137
    Total number of tweets: 7,039
    ThoughtWorks, United States

  • Uta Frith

    94. Uta Frith, Cognitive scientist
    13,000 followers @utafrith
    Citations: 49,700 K-index: 9
    Total number of tweets: 3,645
    University College London, United Kingdom

  • Karen James

    95. Karen James, Biologist
    12,900 followers @kejames
    Citations: 1,032 K-index: 32
    Total number of tweets: 62,600
    Mount Desert Island Biological Laboratory, United States

  • Brian Krueger

    96. Brian Krueger, Genomicist
    12,800 followers @LabSpaces
    Citations: 156 K-index: 59
    Total number of tweets: 35,800
    Duke University, United States

  • Helen Czerski

    97. Helen Czerski, Physicist/oceanographer
    12,300 followers @helenczerski
    Citations: 61 K-index: 76
    Total number of tweets: 2,211
    University College London, United Kingdom

  • Michael Eisen

    98. Michael Eisen, Biologist
    12,300 followers @mbeisen
    Citations: 69,270 K-index: 8
    Total number of tweets: 16,400
    University of California, Berkeley, United States

  • Trisha Greenhalgh*

    99. Trisha Greenhalgh*, Public health scientist
    12,200 followers @trishgreenhalgh
    Citations: 23,930 K-index: 11
    Total number of tweets: 11,700
    Queen Mary University of London, United Kingdom

  • Robert Geller

    100. Robert Geller, Seismologist
    12,100 followers @Rjgeller
    Citations: 6,261 K-index: 17
    Total number of tweets: 3,772
    University of Tokyo, Japan

Some on our list also appear on the 2014 Thomson Reuters Highly Cited Researchers list (*) or the Scholarometer’s top 100 authors (+) ranking, and each is noted with a symbol; Micah Allen had slightly fewer followers than Robert Geller on the day we verified numbers, making Geller #100

Survey methods (adapted from original story):

The list of most followed scientists compiled here is far from scientific. To identify Twitter science stars, we began with celebrity scientists such as Neil deGrasse Tyson and checked out which scientists they followed. We also referenced online lists of scientists to follow on Twitter. Follower number is, of course, a very crude proxy of influence on Twitter, but it’s the most accessible metric for the purpose of this story.

The question of who counts as a scientist is itself a matter of debate. As a general guideline, we included only those who have completed a Ph.D. science degree and have published at least one peer-reviewed paper in a peer-reviewed journal. As an exception to this rule, we excluded professional journalists who fit the above criteria.

We recorded the number of Twitter followers, tweets, and citations for our revised list on 30 September. To tally the number of citations for each scientist, we looked up their Google Scholar profiles or, for those without a profile, used estimates produced by the Publish or Perish software, developed by business professor Anne-Wil Harzing of ESCP Europe. Due to limitations of both methods, the citation numbers are only rough estimates and likely undercount actual citations. This number is particularly problematic for certain names. For example, there’s no easy way to distinguish physicist Brian Cox of the University of Manchester in the United Kingdom from physiologist Brian Cox of the University of Toronto in Canada in calculating the former’s citation count.

The K-index is calculated as follows: In his commentary, using data gathered on 40 scientists, Neil Hall derived a formula for calculating the number of Twitter followers a scientist should have given one’s citation count. The K-index is the ratio of the scientist’s actual follower number to the follower number “warranted” by the citation count.

An Excel document with all the data collected is here.