Short answer
The return shows up in operating numbers, not satisfaction scores: fewer escalations, less rework, faster handoffs, lower turnover among the people you most want to keep. To measure it, pick two or three of those before the training starts, measure them, then measure again afterward. If a provider can’t tell you what they’ll measure before you start, they won’t be able to show you a return when you finish.
The longer answer
There’s a reason to expect a return. Gallup has found that managers account for at least 70% of the variance in employee engagement, so improving that layer reaches everyone below it.
But a general link isn’t your return. Yours comes from the problem you’re trying to fix. That’s why our work starts with a diagnostic that puts a number on the problem, using your own figures, and ends with the same measurement at day 90.