Is this worth doing? The question arises in every domain of life, at every scale, from the smallest and most personal of decisions to the largest and most public. For assessing what—and how much—is worth doing, one useful conceptual tool is a production function. It maps the relationship between units of input (like money, time, or effort) and outputs (whatever you are trying to achieve, from social change to completing a research paper).

People often assume, without thinking about it much, that the relationship between inputs and outcomes will be linear, like figure 1(a), where the output rises by the same incremental amount for each unit of input. If this were true, it would provide clear guidance about what is worth doing. You could make a few inputs, study the results, and then extrapolate outward to predict the full pattern, as in figure 1(b). And if you were getting a flat line, as in figure 1(c), you could just call it a day and move on.

However, production functions are commonly nonlinear.

Think of a bridge. If the inputs are bridge segments, we get no output at all—at least not in the domain of “bridge usefulness”—until we have put together enough segments to span the full chasm or river or alligator pit. And continuing to add extra bridge segments after the span is complete does no further good. The production function looks like figure 2(a), a step function.

Read more at Behavioral Scientist