When something goes wrong at home or at work and there is more than one person or team involved – which it usually is – it should always be analyzed. And it should be clearly stated how much and in what way each of the participant contributed to the fail.
Many people and companies do this. However, what usually happens is, that after everyone says how much they contributed to the issue, when you add it up, it is less than 100 percent. Which obviously cannot be.
When you are evaluating a problem, you should aim for a close up, which will add up to more than a 100 percent. Why? That means, that everyone involved really wants to improve in a way, which will minimize future issues.
Were you responsible for delivering 5 percent of the code? Your responsibility is not 5 percent. And even if you have delivered it, it is not 0.
If you have not delivered it, it is more than 5 percent, because you have probably also blocked other people when not delivering. Or you could have escalated blocker sooner. Or…
If you have delivered it, it is at least 5-10 percent, because you could have helped the rest of the team with something. Or write code, that is easier to understand or integrate. Or document it better. Or…
It is not about blame. It is about responsibility, accountability and ownership. Do not only own your success. Own your failures and your contributions to collective failures. It will help you the most.