selectivity

Etymology

selective + -ity

noun

1. The quality of being selective, or extent to which something is selective.
   […] while music was known to have scientific qualities — harmony, Pythagorean proportional relationship, etc. — it was the musician who by his selectivity made these proportions beautiful, […] 1984, Art International, volume 27, page 53
2. The ability of a radio receiver to separate a desired signal frequency from others.
3. (chemistry) Discrimination of a reactant towards a choice of other reactants; the ratio of rate constants for different reactants.
4. An approach to social work that prioritizes people perceived as having the most need for assistance.
   Proponents of selectivity herald its cost effectiveness; instead of resources being spread over a vast population, money or services can be used where they are most needed. This can help fill in the gaps between needy and non-needy groups. […] Critics of selectivity argue, however, that it may be more cost effective to provide social welfare benefits across the board rather than to spend time and money sorting out those who are "truly disadvantaged." 2015, Philip R. Popple and Leslie Leighninger, quoted in 2016, Karen K. Kirst-Ashman, Empowerment Series: Introduction to Social Work & Social Welfare (page 233)