selectivity

[…] 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, […]

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."