I read with interest the study from Dr Takashi Oshio, where he attempted to address how the association between individual-level social capital and health is confounded by an individual's unobserved time-invariant attributes.1 By reading the methods described by the author, one can find that he operationalised social capital only as two components: bonding and bridging social capital, but he did not mention the third component of social capital: linking social capital. Not measuring this component could confuse …