That’s not quite right. It measures the strength of monotonic relationships, which which may also be linear. So this measure is more general than Pearson correlation. It just measures whether, if one value increases, the other value increases as well, not whether they increase at the same rate.
Spearman (rank) correlation is often a good alternative for nonlinear relationships.
That’s not quite right. It measures the strength of monotonic relationships, which which may also be linear. So this measure is more general than Pearson correlation. It just measures whether, if one value increases, the other value increases as well, not whether they increase at the same rate.