The neglectedness of a problem (also called its uncrowdedness) is the amount of resources currently allocated to solving it. Neglectedness is one of the three factors in the ITN framework.
Christiano, Paul (2014) Neglectedness and impact, 80,000 Hours, January 14.
Oesterheld, Caspar (2020) Complications in evaluating neglectedness, The Universe From an Intentional Stance, June 25.
A blog post noting a number of issues that make the estimation of neglectedness more complicated than it first appears.
Šimčikas, Saulius (2020) A cause can be too neglected, Effective Altruism Forum, April 3.
Although working on a cause tends to produce more value in expectation the more neglected this cause is, the relationship may break down as the cause approaches maximum neglectedness, because of setup costs associated with initiating work on a very novel cause.