For any type of project or initiative that you undertake, it's important to be able to track progress and measure success. In order to do that, you must first outline what success looks like and what metrics you'll use to measure that. Outlining what success looks like starts with: specifying the problems to solve, establishing the objectives, and defining the desired outcomes.
CX initiatives require you to identify and outline those items for (at least) three different constituents, since the initiatives will impact the business, the employee, and the customer. What matters most to each of these?
Some examples of outcomes for each include:
Business
Customers
Employees
Add yours to the list; I'm sure your company, employees, and customers will have plenty of other desired outcomes.
How will you know the outcomes? You will have asked and listened to understand. For employees and customers, you will have used surveys or other listening posts, developed personas, and mapped their journeys. For the business, you will have had discussions with executives to understand where the business' priorities lie. As you already know, executives will want to see how CX initiatives and investments will impact business performance (yes, ROI); if they can't make that connection, it will affect their commitment, including resources to continue to fund and to staff CX improvements initiatives.
Related: What's in Your Customer Experience Strategy Budget?
Now, think about how you'll measure progress toward - and success of - each those outcomes. What does that look like? Here are some examples:
Business
Customer
Employee
Other success metrics
One bit of advice on your metrics: don't wait til the end (outcome achieved, or you think the outcome has been achieved) to see how you're preforming. Check the temperature along the way; track the metrics along the journey. Are you on track to achieving the goals? Are you getting close? If not, what needs to change to ensure that you do? What adjustments do you need to make?
And one more thought: don't get metrics crazy. Pick a couple; keep it simple. Just because you can measure it doesn't mean you should. Track the metrics that give you a solid picture of whether or not you will - or have - achieved the desired outcome. You don't need a three-page spreadsheet filled with a variety of (often irrelevant) metrics to tell you that.