The importance, tractability and neglectedness framework, or ITN framework for short, is a framework for estimating the value of allocating marginal resources to solving a problem based on its importance, tractability, and neglectedness.
When these terms are multiplied, some of the units cancel out, resulting in a quantity denominated in good done per extra person or dollar.
Other differences between Karnofsky's model and Cotton-Barratt's are the terminology ("importance, tractability and uncrowdedness" is replaced by "scale, solvability and neglectedness") and the use of problems rather than causes as the main unit of analysis.
More recently, in an article introducing the SPC framework, Will MacAskill, Teruji Thomas and Aron Vallinder replace neglectedness with leverage, a factor that describes how the work already being done on a problem affects the cost-effectiveness of additional work. The resulting framework generalizes to problems with constant or increasing returns to additional work, whereas the ITN framework remains appropriate for problems with diminishing, especially logarithmic, returns....