Evaluations are built into most coaching processes – either formally or informally.
The coach may ask the executive for feedback at the end of a session that was focused on a personal issue of leadership through which the coach was guiding her or him.

Action Research processes, that set out a project or business goal for change within an organization, test the results, revise the process, and retest, help to define success of a coaching process.

Surveys and interviews of employees, customers and other stakeholders can be done to evaluate outcomes of a coaching process.

The coach and executive can choose and define metric measures to be used at the start of a process, that are designed to objectively measure quantitative results.

There are many ways to evaluate the coaching process from the most informal feedback discussion, to the highly statistical evaluation of quantifying metrics.