Figure 1:

Figure 2:

Figure 3:

Figure 5:

Figure 4:

Results of STERGM formation and persistence for teacher-chosen classrooms_
| Class | Type | Formation (estimate, p-value) | Persistence (estimate, p-value) |
|---|---|---|---|
| 1 | TA | edges (−4.6697, < 1e-04 ***), racial homophily (1.5218, 0.00391 **), triadic closure (0.01252 *) | |
| 2 | TA | edges (−4.66039, 0.000298 ***), non-white outdegree (0.99882, 0.028678 *), mutuality (2.16343, 0.000236 ***) | edges (1.15196, 0.087114+), seating (2.27947, 0.032804 *) |
| 3 | TA | edges (−2.53740,<1e-04 ***), mutuality (1.51807, 0.000251 ***), triadic closure (NA, 0.095127+) | edges (5.54313, 0.003879 **), girl outdegree (−1.87382,0.024540 *) |
| 4 | TA | edges (−4.756824,<1e-04 ***), mutuality (1.325573, 0.008302 **), triadic closure (NA, 0.000146 ***) | |
| 5 | TA | edges (−3.43292, <1e-04 ***), non-white indegree (0.40454, 0.0890+), girl indegree (0.50478, 0.0483 *), mutuality (1.81821, <1e-04 ***), triadic closure (0.40458, 0.0233 *) | |
| 6 | TA | edges (−2.87312, <1e-04 ***), non-white outdegree (0.62196, 0.00597 **), mutuality (1.54773, <1e-04 ***), triadic closure (0.51810, 0.06822+) | mutuality (1.69691, 0.00669 **) |
| 7 | TA | edges (−3.45125, <1e-04 ***), mutuality (1.20579, 0.000859 ***), triadic closure (0.90554, 0.000117 ***) | edges (1.62969, 0.055371+) |
| 8 | TA | edges (−3.23157, <1e-04 ***), 11 grader outdegree (−1.81279, 0.0908+), mutuality (2.16172, <1e-04 ***) | triadic closure (0.83281,0.0105+) |
| 9 | TA | edges (4.3701, < 1e-04 ***), seating (0.4754, 0.02471 *), non-white outdegree (0.8559, 0.00311 **), mutuality (2.5804, < 1e-04 ***), triadic closure (1.2353, 0.00538 **) | |
| 23 | TA | edges (−5.06002, <1e-04 ***), non-white indegree (−0.83548, 0.014202 *), non-white outdegree (1.58795, <1e-04 ***), mutuality (1.38504, 0.001826 **), triadic closure (1.40902, 0.000776 ***) | edges (1.53861, 0.078322+), racial homophily ( −1.15963, 0.063901+), mutuality (1.46604, 0.048401 *), triadic closure (0.58833, 0.032323 * ) |
| 24 | TA | edges (−4.63762, <1e-04 ***), gender homophily (0.87172, 0.00820 **), 9th grader indegree (1.18034, 0.01947 *), girl outdegree (0.68859, 0.03343 *), triadic closure (0.95337, <1e-04 ***) | triadic closure (1.33068, 0.00343 **) |
Results of STERGM formation and persistence for SC classrooms_
| Class | Type | Formation (estimate, p-value) | Persistence (estimate, p-value) |
|---|---|---|---|
| 10 | SC | edges (−3.94281, < 1e-04***), gender homophily (−0.66842, 0.01785*), mutuality (2.35829, < 1e-04***), triadic closure (0.69331, 0.00367**) | |
| 11 | SC | edges (−4.3457168, <1e-04 ***), mutuality (1.7479738,<1e-04 *** ), triadic closure (1.0083759, 0.0231 *) | seating (2.2146689, 0.0740+) |
| 12 | SC | edges (−2.03702,0.03316 *), mutuality (1.83455, 0.00444 **) | triadic closure (1.50379, 0.05099+) |
| 13 | SC | edges (−3.85863, < 1e-04***), mutuality (1.57682, < 1e-04***), triadic closure (1.00728, 0.000146***) | mutuality (3.11584, 0.001632**) |
| 14 | SC | gender homophily (2.2956, 0.00223 **) girls outdegree (−1.8065, 0.01609 *) seating (1.1260, 0.06051+) | |
| 15 | SC | grade homophily (−2.7301, 0.0258 *) | |
| 16 | SC | edges (−4.27543, <1e-04 ***), grade homophily (1.77210, 0.0270 *), mutuality (1.40598, 0.0450 *) | mutuality (2.71069, 0.0107 *) |
| 17 | SC | edges (−3.400596, < 1e-04 ***), 11 grader indegree (−1.999271, 0.04689 *), triadic closure (0.891412, 0.00687 **) | |
| 18 | SC | edges (−3.93163, < 1e-04 ***), seating (−0.77997, 0.031878 *), mutuality (1.41718, 0.001916 **), triadic closure (0.97603, 0.035833 *) | triadic closure (0.68382, 0.035833 *) |
| 19 | SC | edges (−4.02308, <1e-04 ***), gender homophily (0.58180, 0.0784 +), mutuality (2.00926, <1e-04 ***) triadic closure (0.59734, 0.0108 *) | gender homophily (1.64543, 0.0572+), mutuality (2.16391, 0.0440 *) |
| 20 | SC | edges (−1.05228, 0.0117 *), girl outdegree (−0.84408, 0.0323 *) | |
| 21 | SC | edges (−3.86354, <1e-04 ***), gender homophily (0.86038, 0.0128 *), grade homophily (1.69354, <1e-04 ***) | |
| 22 | SC | edges (−3.549671, 0.000752 ***), girl outdegree (1.532272, 0.064955 +) | grade homophily (−2.967090, 0.023639 *) |
STERGM terms tested for the formation and for the persistence of ties_ Note that not all terms were tested for all networks due to size or other constraints (for instance, racial homophily could not be tested for white-only networks)_
| Variables | STERGM term | Diagram | Definition |
|---|---|---|---|
| Edges | edges | The number of edges in the network. | |
| Mutuality | mutual | Probability of bidirectional edge to be formed or mantained | |
| Homophily | nodematch | Probability of formation and persistence of edges within nodes sharing the same attribute (in this case, gender, race, and grade). | |
| Seating proximity | edgecov(seating) | Sum of seating proximity for all edges in the network. | |
| Triadic closure | gwesp.fixed.0.5 | Geometrically weighted edge shared partners. Tests if students form (and keep) edges when they share many common friends. | |
| In-degree | nodeifactor | Differences in in-degree by nodal attribute (in this case, gender, race, and grade). | |
| Out-degree | nodeofactor | Differences in out-degree by nodal attribute (in this case, gender, race, and grade). |
Network attributes changes_
| Class | Type | n | e(S1) | e(S2) | Δ density | Δ mean dist. | Δ mean deg. | Δ centralization |
|---|---|---|---|---|---|---|---|---|
| 1 | TA | 14 | 35 | 47 | 0,0659341 | −0,146808 | 1,714286 | 0,051282 |
| 2 | TA | 14 | 64 | 96 | 0,152381 | −0,323341 | 4,266667 | 0,0357142 |
| 3 | TA | 17 | 49 | 99 | 0,1838235 | −0,93939 | 5,882354 | 0,1083334 |
| 4 | TA | 18 | 55 | 91 | 0,117647 | −1,075059 | 3,999999 | −0,03308823 |
| 5 | TA | 24 | 72 | 142 | 0,1268116 | −0,765732 | 5,83333 | 0,04940714 |
| 6 | TA | 24 | 89 | 185 | 0,173913 | −0,722117 | 8,000003 | −0,04743086 |
| 7 | TA | 22 | 70 | 142 | 0,1558441 | −1,420978 | 6,545454 | 0,07142858 |
| 8 | TA | 18 | 65 | 88 | 0,0751634 | −0,283273 | 2,555556 | 0,0569852 |
| 9 | TA | 24 | 97 | 201 | 0,1884058 | −0,744438 | 8,666667 | 0,0158103 |
| 10 | SC | 20 | 51 | 104 | 0,1394737 | −0,493138 | 5,3 | 0,06871347 |
| 11 | SC | 18 | 67 | 131 | 0,2091504 | −0,591145 | 7,111116 | −0,0183823 |
| 12 | SC | 13 | 35 | 53 | 0,1153846 | 0,004831 | 2,769231 | 0,030303 |
| 13 | SC | 24 | 82 | 165 | 0,1503623 | −1,26794 | 6,916667 | 0,01284585 |
| 14 | SC | 11 | 20 | 36 | 0,1454545 | 0,253086 | 2,909091 | −0,0277777 |
| 15 | SC | 8 | 14 | 19 | 0,0892857 | −0,209184 | 1,25 | 0,13095238 |
| 16 | SC | 16 | 50 | 54 | 0,0166667 | 0,463289 | 0,5 | −0,0095238 |
| 17 | SC | 18 | 57 | 82 | 0,0816994 | −0,608628 | 2,777778 | 0,0202206 |
| 18 | SC | 22 | 79 | 110 | 0,0670995 | −0,898577 | 2,818182 | 0,0154762 |
| 19 | SC | 18 | 47 | 72 | 0,0816993 | −0,281671 | 2,777778 | −0,01286769 |
| 20 | SC | 15 | 41 | 77 | 0,1714286 | −0,767532 | 4,800003 | 0,02472531 |
| 21 | SC | 26 | 70 | 96 | 0,04 | −1,1696 | 2 | 0 |
| 22 | SC | 14 | 37 | 30 | −0,038462 | −0,637253 | −1 | −0,0673077 |
| 23 | TA | 19 | 77 | 121 | 0,128655 | −0,32748 | 4,631577 | 0,0212418 |
| 24 | TA | 20 | 60 | 81 | 0,0552632 | −0,826451 | 2,1 | −0,001462 |
Network assortativity changes_
| Class | Type | Δ gender assortativity | Δ race assortativity | Δ grade assortativity |
|---|---|---|---|---|
| 1 | TA | −0,12992152 | −0,1138759 | NA |
| 2 | TA | −0,2800093 | −0,0044844 | NA |
| 3 | TA | 0,010200081 | −0,27768636 | NA |
| 4 | TA | 0,07025436 | 0,0120824 | NA |
| 5 | TA | −0,21661889 | −0,0863014 | NA |
| 6 | TA | −0,19435523 | −0,28064122 | NA |
| 7 | TA | −0,05244456 | NA | −0,1888698 |
| 8 | TA | −0,2323466 | NA | 0,01198873 |
| 9 | TA | −0,14999934 | −0,223815 | NA |
| 10 | SC | −0,450792526 | −0,4044041 | NA |
| 11 | SC | −0,17527807 | −0,059338 | NA |
| 12 | SC | −0,1508002 | −0,349391 | −0,2033669 |
| 13 | SC | −0,079262478 | −0,4754838 | NA |
| 14 | SC | 0,2349064 | NA | −0,8430588 |
| 15 | SC | −0,5266441 | NA | −0,74261296 |
| 16 | SC | −0,1831539 | NA | 0,1267994 |
| 17 | SC | −0,3295782 | NA | −0,1149261 |
| 18 | SC | −0,239163 | NA | −0,0921452 |
| 19 | SC | 0,0296049 | NA | −0,3941588 |
| 20 | SC | −0,1588119 | NA | NA |
| 21 | SC | −0,1311118 | NA | −0,1616417 |
| 22 | SC | 0,13544486 | NA | −0,2851677 |
| 23 | TA | −0,006702639 | −0,00981007 | NA |
| 24 | TA | 0,0101957 | NA | −0,3874417 |
Descriptive characteristics of the classrooms studied, including the name of the class, aimed grade, seating type, number of respondents, number of missing longitudinal data, percentage non-white, percentage woman, and percentage not in the aimed grade level for the class_
| Class | Name | Aimed grade | Type | Respondents | Missing | Non-white (%) | Woman (%) | Not in aimed level (%) |
|---|---|---|---|---|---|---|---|---|
| 1 | Biology | 10th | TA | 14 | 2 | 35,7 | 64,28 | 7,1 |
| 2 | Biology | 12th | TA | 14 | 0 | 35,7 | 64,28 | 0 |
| 3 | English | 12th | TA | 17 | 3 | 52,9 | 58,8 | 0 |
| 4 | English | 10th | TA | 18 | 1 | 38,8 | 72,2 | 0 |
| 5 | Trigonometry | 10th | TA | 24 | 1 | 37,5 | 54,1 | 0 |
| 6 | English | 10th | TA | 24 | 3 | 41,6 | 54,1 | 0 |
| 7 | Chemistry | 10th | TA | 22 | 1 | 0 | 50 | 18,1 |
| 8 | Chemistry | 10th | TA | 18 | 0 | 5,5 | 50 | 5,5 |
| 9 | AP English | 12th | TA | 24 | 1 | 37,5 | 79,1 | 0 |
| 10 | Discrete Mathematics IB | 12th | SC | 20 | 2 | 55 | 55 | 0 |
| 11 | Calculus IB | 12th | SC | 18 | 3 | 33,3 | 27,77 | 0 |
| 12 | Algebra II | 10th | SC | 13 | 0 | 46,1 | 61,5 | 15,3 |
| 13 | US History II IB | 12th | SC | 24 | 3 | 41,6 | 79,1 | 0 |
| 14 | Precalculus | 12th | SC | 11 | 0 | 0 | 63,6 | 27,3 |
| 15 | Precalculus | 12th | SC | 8 | 2 | 12,5 | 62,6 | 75 |
| 16 | Biology II | 12th | SC | 16 | 0 | 5,5 | 68,7 | 31,2 |
| 17 | Trigonometry | 10th | SC | 18 | 2 | 5,5 | 55,5 | 22,2 |
| 18 | Chemistry | 10th | SC | 22 | 3 | 4,5 | 50 | 31,8 |
| 19 | Physics | 12th | SC | 18 | 3 | 5,5 | 66,6 | 22,2 |
| 20 | Calculus | 12th | SC | 15 | 1 | 6,6 | 60 | 0 |
| 21 | Geometry | 10th | SC | 26 | 2 | 7,6 | 50 | 50 |
| 22 | Algebra B | 10th | SC | 14 | 2 | 0 | 50 | 35,7 |
| 23 | Biology | 10th | TA | 19 | 0 | 42,1 | 63,1 | 0 |
| 24 | Geometry | 10th | TA | 20 | 1 | 0 | 45 | 45 |