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 views32699
    Project overview1573
    Matrix views674Matrix landing page (614 views); Bat Skull Matrix (60 views);
    Media views19786Media search (1606 views); M435071 (204 views); M435131 (172 views); M435137 (170 views); M435118 (153 views); M435083 (220 views); M435129 (171 views); M435095 (185 views); M435084 (190 views); M435053 (209 views); M435086 (211 views); M435107 (165 views); M435135 (164 views); M435141 (163 views); M435127 (172 views); M435113 (165 views); M435054 (215 views); M435064 (226 views); M435146 (178 views); M435124 (198 views); M435136 (167 views); M435089 (192 views); M435076 (202 views); M435085 (230 views); M435058 (227 views); M435068 (211 views); M435057 (211 views); M435106 (174 views); M435130 (182 views); M435104 (189 views); M435087 (246 views); M435116 (159 views); M435122 (176 views); M435142 (174 views); M435088 (222 views); M435060 (208 views); M435133 (167 views); M435070 (218 views); M435072 (226 views); M435063 (181 views); M435145 (162 views); M435081 (215 views); M435069 (223 views); M435138 (178 views); M435126 (158 views); M435147 (169 views); M435056 (245 views); M435108 (170 views); M435140 (164 views); M435091 (214 views); M435062 (202 views); M435111 (170 views); M435143 (171 views); M435082 (209 views); M435094 (182 views); M435080 (196 views); M435128 (174 views); M435059 (216 views); M435066 (214 views); M435125 (160 views); M435144 (183 views); M435067 (191 views); M435114 (202 views); M435061 (225 views); M435109 (167 views); M435090 (185 views); M435134 (179 views); M435077 (183 views); M435098 (184 views); M435123 (150 views); M435100 (182 views); M435119 (164 views); M435115 (174 views); M435096 (176 views); M435078 (205 views); M435074 (185 views); M435105 (173 views); M435112 (216 views); M435097 (181 views); M435148 (174 views); M435110 (195 views); M435055 (237 views); M435099 (185 views); M435093 (208 views); M435065 (211 views); M435121 (172 views); M435073 (189 views); M435132 (166 views); M435102 (190 views); M435092 (194 views); M435075 (199 views); M435120 (176 views); M435101 (193 views); M435117 (172 views); M435079 (205 views); M435139 (157 views); M435103 (167 views);
    Taxon list3595
    Specimen list4494
    Views for media list573
    Documents list563

    Project downloads

    type number of downloads Individual items downloaded (where applicable)
    Total downloads from project177
    Project downloads164
    Matrix downloads11Bat Skull Matrix (11 downloads);
    Document downloads2Supplementary material (2 downloads);