Hi Mark, I’m not quite sure I understand but here’s what I got: your boss likes to measure productivity solely by how many tasks you’ve crossed off a to-do list but the nature of your work makes it difficult to complete a large number of tasks each day since projects are more long-term than short-term?
If this is the case, I’d ask if you have any control over what tasks end up on that list? If so, maybe try breaking a project up into smaller goals that can reasonably be completed on the short-term scale your boss is looking for. That way you demonstrate that your team is making progress each day, albeit on a more reasonable time frame that doesn’t require you to put in 70-hour weeks (that sounds like a nightmare).
If all else fails, maybe bring a specific project to your boss’ attention as an example to show how your team has been processing your workload. It may just be that your boss isn’t filled in on the nature of your work since you’re the expert on it. He may agree on a more reasonable metric once the nuances of your role’s timeline have been explained.
Unfortunately I can’t claim to be a true expert on this topic but I hope something I’ve recommended is of some value to you or pushes you in a direction that’s ultimately helpful! Feel free to reply if I misunderstood your comment!