1. The size of business expenditure.
How much money are you spending on the thing you are planning to measure?
For Marketing it is a bit easy to figure this out. You want to measure messaging vibrancy of your Facebook campaign. Okay. How much money are you spending on this campaign? $150,000. Excellent.
Don't measure messaging vibrancy. It turns out messaging vibrancy is very hard to measure - even if it is cleanly defined. The size of that spend does not justify investing in this analytics project. Just measure Conversation Rate and Amplification Rate and call it a day.
If you were going to spend $1,500,000, the decision changes.
Apply that thinking to your Finance team wanting to measure Customer Lifetime Value - what is the size of spending decision that project is expected to influence? (Even better, what is the size of the Profit that project is expected to influence?)
Consider the size of spend your Comms team is putting into a High Value Influencers project. The project is great, is their desire to measure change in perception justified by the $275k they are putting into the project?
The size of business spend is a proxy for: How important is this initiative in the grand scheme of things?
If the answer is the initiative will be 20% of the entire year's marketing (or whatever) spend, then certainly consider a commensurate investment in a complex analytics project.
If the answer is that the initiative will be a small part of the entire budget, use the highest quality of data that's already available and call it a day.
It might only be a Win-Small Loss-Win. But, it is the choice a smart Extremely Senior Leader (ESL) would make.