> it's important because they've put an actual dollar amount to its return on investment.
The issue isn't whether you can put a dollar amount, but on the confidence in accuracy. I've seen how this is done in my company: Construct a narrative, assign numbers to that narrative (with some justification that doesn't always involve real world data), and come up with a total. They are incentivized to inflate the numbers as their goal is to increase their budget - not be accurate. If all departments did this, and you add the numbers they come up with, we'd easily end up with a number 10x our annual revenue, which is ridiculous.
Some folks who are not vested in this will aim for accuracy. And even then, they will have a large confidence interval - easily off by 2x.
How are you going to go from there and estimate an employee's value? Even if the project's value was 100% accurate, you still need to break that down to each employee. And since most employees don't work independently, you need to model the interaction effects (my work depends on your work - if you perform poorly, my contribution to the bottom line is reduced).
If the estimate of the value of the project is off by 2x, then you've already got a pathetic lower bound on the interval length of your confidence interval.
Alexa is actually an easier case to model. My job is to improve the internal communications infrastructure so that important messages get delivered (IT announcements, CEO communications, etc). How will you model my contribution to the bottom line?
I can assure everyone: At any decent sized company, no one is trying to come up with your value to the company.