Table of results for comparisons between citizen-scientist data and data collected by expert staff, listed from highest to lowest % agreement. The number of times a presence/absence variable was noted as ‘Present’ by staff and citizen scientists is included to provide additional clarification for % Agreement results, which tend to be higher for those variables present in fewer cases, even in cases where Sn and PPV were low. n = 2872 for all variables except for DBH (n = 2913 due to the inclusion of dead trees) and Species (n = 2702 due to some specimens only being identified to genus level).
| Assessment variable | Percentage agreementz | Sn (%) | Sp (%) | PPV(%) | NPV (%) | Staff presence (n) | Citizen scientist presence (n) |
|---|---|---|---|---|---|---|---|
| Trunk Problem: Lightsy | 99.8 | 80.0 | 99.9 | 50.0 | 100 | 5 | 8 |
| Root Problem: Metal Gratesy | 99.2 | 66.7 | 99.3 | 23.1 | 99.9 | 9 | 26 |
| Trunk Problem: Rope/Wiresy | 96.4 | 25.0 | 97.3 | 10.6 | 99.0 | 36 | 85 |
| DBH (2.54 cm tolerance) | 92.7 | -- | -- | -- | -- | -- | -- |
| Root Problem: Othery | 91.9 | 29.4 | 92.6 | 4.6 | 99.1 | 34 | 219 |
| Branch Problem: Othery | 91.2 | 35.2 | 92.3 | 8.1 | 98.7 | 54 | 236 |
| Trunk Problem: Othery | 89.4 | 40.0 | 90.1 | 6.1 | 99.0 | 45 | 297 |
| Branch Problem: Lights/Wiresy | 89.4 | 59.4 | 90.7 | 23.0 | 98.0 | 128 | 330 |
| Tree Guards | 87.8 | -- | -- | -- | -- | -- | -- |
| Genus | 86.5 | -- | -- | -- | -- | -- | -- |
| Stewardshipx | 80.6 | 79.9 | 80.9 | 70.3 | 87.7 | 1037 | 1159 |
| Species | 77.6 | -- | -- | -- | -- | -- | -- |
| Tree Condition | 74.9 | -- | -- | -- | -- | -- | -- |
| Root Problem: Stonesy | 73.7 | 63.0 | 76.1 | 37.3 | 90.1 | 529 | 893 |
| Sidewalk Damage | 73.3 | 58.3 | 81.0 | 61.3 | 79.0 | 931 | 979 |
| DBH (exact) | 32.0 | -- | -- | -- | -- | -- | -- |
↵z Citizen-scientist percentage agreement with NYC Parks’ staff.
↵y These assessment variables are sub-variables of Tree Problems.
↵x Stewardship was converted to presence/absence for analysis because some signs of stewardship were ephemeral (for example, witnessing a steward watering or weeding a tree), and would likely not be present during both rounds of data collection, though the quantity category data will be used operationally.