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 views40083
    Project overview1792
    Matrix views792Matrix landing page (721 views); Bat Skull Matrix (71 views);
    Media views24885Media search (2128 views); M435071 (252 views); M435131 (216 views); M435137 (212 views); M435118 (193 views); M435083 (270 views); M435129 (213 views); M435095 (226 views); M435084 (241 views); M435053 (261 views); M435086 (268 views); M435107 (204 views); M435135 (205 views); M435141 (205 views); M435127 (218 views); M435113 (210 views); M435054 (269 views); M435064 (282 views); M435146 (219 views); M435124 (240 views); M435136 (210 views); M435089 (244 views); M435076 (252 views); M435085 (284 views); M435058 (283 views); M435068 (341 views); M435057 (264 views); M435106 (217 views); M435130 (219 views); M435104 (229 views); M435087 (299 views); M435116 (198 views); M435122 (218 views); M435142 (212 views); M435088 (275 views); M435060 (261 views); M435133 (205 views); M435070 (272 views); M435072 (284 views); M435063 (234 views); M435145 (204 views); M435081 (269 views); M435069 (277 views); M435138 (219 views); M435126 (198 views); M435147 (209 views); M435056 (296 views); M435108 (210 views); M435140 (204 views); M435091 (267 views); M435062 (253 views); M435111 (212 views); M435143 (214 views); M435082 (265 views); M435094 (226 views); M435080 (249 views); M435128 (212 views); M435059 (269 views); M435066 (272 views); M435125 (201 views); M435144 (224 views); M435067 (244 views); M435114 (244 views); M435061 (277 views); M435109 (210 views); M435090 (242 views); M435134 (219 views); M435077 (236 views); M435098 (228 views); M435123 (201 views); M435100 (226 views); M435119 (206 views); M435115 (217 views); M435096 (221 views); M435078 (268 views); M435074 (234 views); M435105 (213 views); M435112 (260 views); M435097 (225 views); M435148 (256 views); M435110 (237 views); M435055 (294 views); M435099 (225 views); M435093 (253 views); M435065 (264 views); M435121 (213 views); M435073 (239 views); M435132 (208 views); M435102 (230 views); M435092 (246 views); M435075 (252 views); M435120 (215 views); M435101 (229 views); M435117 (207 views); M435079 (258 views); M435139 (196 views); M435103 (209 views);
    Taxon list4092
    Specimen list5389
    Views for media list696
    Documents list668

    Project downloads

    type number of downloads Individual items downloaded (where applicable)
    Total downloads from project251
    Project downloads238
    Matrix downloads11Bat Skull Matrix (11 downloads);
    Document downloads2Supplementary material (2 downloads);