Project 2577: M. A. O’Leary, K. Alphonse, A. H. Mariangeles, D. Cavaliere, A. Cirranello, T. G. Dietterich, M. Julius, S. Kaufman, E. Law, M. Passarotti, A. Reft, J. Robalino, N. B. Simmons, S. Y. Smith, D. W. Stevenson, E. Theriot, P. M. Velazco, R. L. Walls, M. Yu, M. Daly. 2018. Crowds Replicate Performance of Scientific Experts Scoring Phylogenetic Matrices of Phenotypes. Systematic Biology. 67 (1):49-60.
Specimen: Kerivoula hardwickii (AMNH/Mammalogy:107483)
View: Skull-dorsal


Scientists building the Tree of Life face an overwhelming challenge to categorize phenotypes (e.g., anatomy, physiology) from millions of living and fossil species. This biodiversity challenge far outstrips the capacities of trained scientific experts. Here we explore whether crowdsourcing can be used to collect matrix data on a large scale with the participation of the non-expert students, or “citizen scientists.” Crowdsourcing, or data collection by non-experts, frequently via the internet, has enabled scientists to tackle some large-scale data collection challenges too massive for individuals or scientific teams alone. The quality of work by non-expert crowds is, however, often questioned and little data has been collected on how such crowds perform on complex tasks such as phylogenetic character coding. We studied a crowd of over 600 non-experts, and found that they could use images to identify anatomical similarity (hypotheses of homology) with an average accuracy of 82% compared to scores provided by experts in the field. This performance pattern held across the Tree of Life, from protists to vertebrates. We introduce a procedure that predicts the difficulty of each character and that can be used to assign harder characters to experts and easier characters to a non-expert crowd for scoring. We test this procedure in a controlled experiment comparing crowd scores to those of experts and show that crowds can produce matrices with over 90% of cells scored correctly while reducing the number of cells to be scored by experts by 50%. Preparation time, including image collection and processing, for a crowdsourcing experiment is significant, and does not currently save time of scientific experts overall. However, if innovations in automation or robotics can reduce such effort, then large-scale implementation of our method could greatly increase the collective scientific knowledge of species phenotypes for phylogenetic tree building. For the field of crowdsourcing, we provide a rare study with ground truth, or an experimental control that many studies lack, and contribute new methods on how to coordinate the work of experts and non-experts. We show that there are important instances in which crowd consensus is not a good proxy for correctness.

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Article DOI: 10.1093/sysbio/syx052

Project DOI: 10.7934/P2577,
This project containsMatrices
  • 96 Media
  • 1 Matrix
  • 1 Document
  • 6 Taxa
  • 15 Specimens
  • 20 Characters
Total size of project's media files: 297.77M

Download Project SDD File
Total scored cells: 140
Total media associated with cells: 122
Total labels associated with cell media: 148
Total characters: 20
Total characters with associated media: 20
Total characters with media with labels: 0
Total character states: 55
Total character states with associated media: 52
Total character states with media with labels:0
Total unordered/ordered characters:20/0
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MorphoBank Project 2577

    This research
    supported by

    Authors' Institutions

    • Ohio State University

    • Oregon State University

    • University of Arizona

    • University of Michigan

    • University of Texas at Austin

    • University of Waterloo

    • American Museum of Natural History

    • Drexel University

    • Kenx Technology Inc

    • New York Botanical Garden

    • St. Cloud State University

    • Stony Brook University

    • Whirl-i-gig

    • College of William and Mary

    • Howard Hughes Medical Institute


    member name taxa specimens media chars character
    cell scorings
    (scored, NPA, "-")
    Andrea Cirranello
    Project Administrator
    (0, 0, 0)
    Maureen O'Leary
    Full membership
    (0, 0, 0)
    Nancy Simmons
    Full membership
    (0, 0, 0)
    Paul Velazco
    Full membership
    (0, 0, 0)

    Taxonomic Overview for Matrix 'M24371' (6 Taxa)

    taxon unscored
    no cell
    "-" cellscell images labels on
    cell images
    [1] Cynopterus sphinx
    Last Modified in 12/21/16
    [2] Saccopteryx bilineata
    Last Modified in 12/21/16
    [3] Trachops cirrhosus
    Last Modified in 12/21/16
    [4] Kerivoula hardwickii
    Last Modified in 12/21/16
    [5] Miniopterus schrebersii
    Last Modified in 12/21/16
    [6] Erinaceus europaeus
    Last Modified in 12/21/16

    Project views

    type number of views Individual items viewed (where applicable)
    Total project views46345
    Project overview2018
    Matrix views951Matrix landing page (810 views); Bat Skull Matrix (141 views);
    Media views28986Media search (2534 views); M435071 (291 views); M435131 (252 views); M435137 (249 views); M435118 (228 views); M435083 (305 views); M435129 (247 views); M435095 (256 views); M435084 (278 views); M435053 (305 views); M435086 (311 views); M435107 (240 views); M435135 (243 views); M435141 (243 views); M435127 (249 views); M435113 (246 views); M435054 (313 views); M435064 (326 views); M435146 (254 views); M435124 (276 views); M435136 (247 views); M435089 (283 views); M435076 (293 views); M435085 (325 views); M435058 (327 views); M435068 (409 views); M435057 (306 views); M435106 (252 views); M435130 (254 views); M435104 (265 views); M435087 (339 views); M435116 (235 views); M435122 (255 views); M435142 (246 views); M435088 (317 views); M435060 (299 views); M435133 (242 views); M435070 (314 views); M435072 (331 views); M435063 (286 views); M435145 (238 views); M435081 (312 views); M435069 (321 views); M435138 (254 views); M435126 (233 views); M435147 (244 views); M435056 (339 views); M435108 (245 views); M435140 (238 views); M435091 (306 views); M435062 (296 views); M435111 (248 views); M435143 (247 views); M435082 (315 views); M435094 (258 views); M435080 (291 views); M435128 (247 views); M435059 (314 views); M435066 (313 views); M435125 (238 views); M435144 (259 views); M435067 (281 views); M435114 (278 views); M435061 (320 views); M435109 (245 views); M435090 (288 views); M435134 (255 views); M435077 (278 views); M435098 (262 views); M435123 (236 views); M435100 (255 views); M435119 (247 views); M435115 (251 views); M435096 (254 views); M435078 (309 views); M435074 (275 views); M435105 (248 views); M435112 (300 views); M435097 (258 views); M435148 (296 views); M435110 (274 views); M435055 (346 views); M435099 (257 views); M435093 (288 views); M435065 (309 views); M435121 (249 views); M435073 (280 views); M435132 (245 views); M435102 (265 views); M435092 (287 views); M435075 (295 views); M435120 (251 views); M435101 (266 views); M435117 (233 views); M435079 (303 views); M435139 (229 views); M435103 (246 views);
    Taxon list4513
    Specimen list6316
    Views for media list794
    Documents list744

    Project downloads

    type number of downloads Individual items downloaded (where applicable)
    Total downloads from project282
    Project downloads269
    Matrix downloads11Bat Skull Matrix (11 downloads);
    Document downloads2Supplementary material (2 downloads);