Effectiveness

When something is deemed effective, it means it has an intended or expected outcome, or produces a deep, vivid impression.

In medicine, effectiveness relates to how well a treatment works in practice, especially as shown in pragmatic clinical trials, as opposed to efficacy, which measures how well it works in explanatory clinical trials or research laboratory studies.

[6] For example, Utica University in New York State holds that "an effective institution is characterized by a clearly defined mission that articulates who it serves, what it aspires to be, and what it values.

[6] Pope Francis adopts the same term in a critique of governmental effectiveness when he refers to "a number of countries [with] a relatively low level of institutional effectiveness", which leads to "greater problems for their people while benefiting those who profit from this situation".

[12] Other synonyms for effectiveness include: clout, capability, success, weight, performance.

To illustrate: suppose, you build 10 houses, very fast and cheap (efficient), but no one buy them.