  According to traditional balance theory, individual social actors avoid
establishing triads with an odd number of negative links. Generalising,
mesoscopic balance is realised when the nodes of a signed graph can be grouped
into positively connected subsets, mutually connected by negative links. If
this prescription is interpreted rigidly without allowing for statistical
noise, it quickly dismisses most real graphs as frustrated. As an alternative,
a relaxed, yet qualitative, definition of balance has been advanced. After
rephrasing both variants in statistically testable terms, we propose an
inference scheme to unambiguously assess if a signed graph is traditionally or
relaxedly balanced.
