Accuracy of best performing models (ntrain = 20000) in identifying opposite-gender peers (OGP) and predicting the age of the younger user (YUA) for each relationship as inferred from a pair’s age and gender difference.

For peers, + indicates same-gender pairs, while − indicates opposite-gender pairs. Y corresponds to pairs where the younger user is in the age range 18–28; M, 29–45; L, 46–55; O, 56–79. Peers are indicated by “peers”, while parent-child relationships are denoted by “child”. Note that in the latter case, it is the age group of the child that is given, while the parent is at least 20 years older. For the YUA prediction, we also include information about the composition and accuracy found for the subgroups of those in age group M corresponding to cases where the YUA is below and at least 35 years old.