The “core” Jewish population includes people who self-identify as Jewish in social surveys, and do not have another monotheistic religion. It also includes people who may not recognise themselves as Jewish, but have Jewish parents and have not adopted a different religious identity. It further includes all converts to Judaism by any procedure, as well as other people who declare themselves to be Jewish even without having undergone conversion.

Everyone within the core Jewish population is included, but so is anyone born to at least one Jewish parent – mother or father – who considers themselves to be partly Jewish. This population measure is quite a recent addition to Jewish demographic analysis and was developed in response to the desire within parts of the Jewish community to be more open and inclusive to the growing number of people who have this partial relationship to Jewishness due to their mixed parentage.

This figure includes the sum of (a) the 'core' Jewish population of a certain country; (b) all people with Jewish parents who do not self-identify as Jews today; and (c) all their non-Jewish household members (spouses, children etc.)

The right to claim Israeli citizenship applies to anybody who descends from at least one Jewish grandparent, and it extends to the immediate families of those individuals as well. This legislation may be particularly pertinent if Jews in a certain country see a reason to activate this right and immigrate to Israel.