Effect

A new CEO takes over a struggling company. She does not just suggest changes; she reorganizes departments, replaces outdated software, and launches new products. Within a year, profits rise, morale improves, and the company becomes competitive again. She did not merely try — she made the transformation happen. What did the CEO do? She effected a turnaround.

Exert (to apply pressure or force, often without guaranteeing the outcome) contrasts with effect, which means to successfully bring about a planned change or result. Effect emphasizes completion and achievement, while exert focuses on the effort or application of force, regardless of the final outcome.