When prioritizing causes, what we ultimately care about is how much good we can do per unit of resources. In formal terms, we want to find the causes with the highest marginal utility per dollar, $M U / $$ (or, marginal cost-effectiveness). The Importance-Tractability-Neglectedness (ITN) framework has been used as a way of calculating $M U / $$ by estimating its component parts. In this post I...

(see also recent posts by John Halstead and Michael Plant).

80k defines ITN as follows:

Importance = utility gained / % of problem solved
Tractability = % of problem solved / % increase in resources
Neglectedness = % increase in resources / extra $

With these definitions, multiplying all three factors gives us utility gained / extra $, or MU/$ (as the middle terms cancel out). However, I will make two small amendments to this setup. First, it seems artificial to have a term for "% increase in resources", since what we care about is the per-dollar effect of our actions. Hence, we can instead define tractability as "% of problem solved / extra $", and eliminate the third factor from the main definition. So to calculate MU/$, we simply multiply importance and tractability:

$M U / $ =$ $\frac{utility gained}{% of problem solved}$ $\times$ $\frac{% of problem solved}{extra $}$

This defines MU/$ as a function of the amount of resources allocated to a problem, which brings me to my second amendment. Apart from the above definition, 80k defines 'neglectedness' informally as the amount of resources allocated to solving a problem. This definition is confusing, because the everyday meaning of 'neglected' is "improperly ignored". To say that a cause is neglected intuitively means that it is ignored relative to its cost-effectiveness. But if neglectedness is supposed to be a proxy for cost-effectiveness, this everyday meaning is circular. And really, how useful is the advice to focus on causes that have been improperly ignored?

I suggest we instead use "crowdedness" to mean the amount of resources allocated to a problem. This captures intuitions about diminishing returns (other things equal, a more crowded cause is less cost-effective), and avoids the problem of having a relative standard as the everyday meaning.

Thus, our revised framework is now ITC:

Importance = utility gained / % of problem solved
Tractability = % of problem solved / $
Crowdedness = $

...

Intro to cause prioritization