I really like this article. To summarize it:

Author contends

- Managers (etc) try to quantify engineers' productivity. Even though some are 10x better, quantifying from the outside is an impossible quest.

- Developers are treated like blue collar workers and that when viewed as professionals (doctors, lawyers) it's more readily apparent why it's so hard it is to assign a number to the quantity and quality their craft.

- There are several ways to help developers be more productive such as tracking and removing impediments. These methods are essentially Kanban.