Effective On-Task Time
Software development is knowledge work. We use knowledge, take input as knowledge, and the output we produce is knowledge. Our output is executable knowledge. According to Peter Drucker, the 21st century's defining characteristic is knowledge work. We, software engineers, are right in the middle of it. Drucker writes that manual worker productivity during the 20th century increased 50 times. He admonishes us to improve knowledge worker productivity during this century as much as we improved manual worker productivity during the last century. He postulates that the developed nations of the future will be those that will make their knowledge workers productive.
Unfortunately, we seem to have a hard time measuring productivity. Economists have a straightforward measure of productivity: the value of the output divided by the time required to create it, expressed in dollars per hour. We need to figure out how to make this definition operational for software developers. A component of this measure is time.
Let's start with Effective On-Task Time or EOT. This is the time that you spend creating the deliverable that is the target of your task. You keep this number pure, devoid of anything that didn't directly contribute to the output. Your objective is to measure the time that the task took. You can find references to the concept of "Task Time" in a number of places. Watts Humphrey writes that "task time is what engineers spend working on scheduled tasks."
And herein lies the heart of the matter: EOT is about working on something that you planned to work on. It is about your ability to meet a commitment. The plan is your commitment. The time that it took to complete the task is reflective of your ability to understand the work required to meet that commitment.
EOT doesn't include time for any activities that don't matter to the work of creating that deliverable. The interruptions from your co-worker, phone calls, and breaks don't count. Some of the activities may tangentially work toward it, but your objective is not to account for every minute, but rather to count those distinct minutes when you know that you are moving the needle forward.
At the end of the day, EOT matters first and foremost for you. It helps you understand how good you are, how well you understand your work. It builds your confidence. When you repeatedly make aggressive plans and meet them, you know that you are becoming the engineer that you always wanted to be: outstanding.