Modularity values.

(A) Q+ values for Newman (circles) and greedy (squares) methods. (B) Q-signed values for Newman (circles) and greedy (squares) methods. (C) Percentage of negative links perturbation in the communities (PPC) for Newman (circles) and greedy (squares) methods. Each greedy value was obtained after 300 simulations.</p

Boxplot for Louvain method.

Figures showing the variability of the Louvain method. (PDF)</p

Heuristic to add negative missing links.

Blue and red links represent reciprocal friendship (best friend) and enmity (worst enemy) relations respectively. The red dotted line represents a one-way negative link (enemy), that is, only one student said he was an enemy of the other. The figure shows that, if it were reciprocal, there would be three balanced triads and one unbalanced. In this case, the one-way negative link becomes reciprocal negative link. Modified image from [35].</p

Dunbar’s ratios for experimental data.

(A) Values obtained by dividing friend by best friends relationships. (B) Values obtained by dividing enemy by worst enemy relationships. The dashed line is Dunbar’s ratio of three.</p

Louvain algorithm calibration.

(A) Elementary school esIZ calibration, the optimal resolution value is 0.85. (B) Secondary school ssRDS calibration, the optimal resolution value is 1.20. (C) University usTRS calibration, the optimal resolution value is 1.30. Each value was obtained after 300 simulations.</p

Adjacency matrix.

Signed adjacency matrices used in the study (.cvs). (ZIP)</p

Positive and negative links in the signed communities.

Positive and negative links in the signed communities.</p

Characteristics of the schools that participated in this study.

Characteristics of the schools that participated in this study.</p

Dunbar’s ratios for negative missing links.

Values obtained by dividing enemy by worst enemy relationships. Calculations for secondary and high schools and university were obtained including the missing links. The dashed line is Dunbar’s ratio of three.</p

Signed communities examples.

(A) Four signed communities from esRRC elementary school (Newman method). Communities with negative hubs and with two antagonistic subgroups are observed. (B) Four signed communities from ssTN2 high school (greedy method). There are phenomena similar to the previous one but in smaller quantity.</p