Ipseus assesses, by way of customised identity instruments, how the individuals appraise themselves and attribute characteristics to other agencies of meaningful relevance to them. It does this in terms of ISA concepts: importance or significance of others to people's sense of identity ('ego-involvement with the other'); 'evaluation of the other' in terms of positive or negative attributes; 'identification with the other' in 'aspirational' and 'empathetic' modes; 'conflicted identification with the other'; values and beliefs they hold as 'core' or 'conflicted dimensions of identity' (introducing the new concept of 'structural pressure'); extents to which people's identities are 'diffuse' and conflicted, or defensive and rigid. Each of these parameters is unambiguously defined and translated into algorithms, which are represented within the ipseus computer source code. A particular feature of the ISA approach is that the qualitative features of identity are integrated with the quantitative parameters, so the qualitative aspects remain overt in the ipseus output together with the quantitative parametric indices of identity.