Accountability vs. Responsibility -- What's the Difference?
In the real world, it is expected that people in day to day interactions - whether the people who receive financial investments, the people who work for a firm, or the people who provide services to others - to suffer or benefit from the consequences of their actions to varying degrees. However, depending on the context of these relationships, there is disagreement on how much a person should be blamed in the events of a failure, or how much that person should be rewarded in cases of success.
Part of this distinction stems from the differences in accountability and responsibility.
Accountability
Accountability can most succinctly and precisely be described as answerability. Having accountability exclusively means a necessity and expectation to explain one's actions for whatever they are accountable for. An easy way to think about being accountable is literally - whatever the results of a person's actions, that person must be able to give an account of not just what happened, but why it happened and how.
By this definition, a CEO can do a terrible job as an executive of a company, allow it to fall into ruin, and squander all of its fund and assets - but still be accountable, if they are up for the task of simply explaining what happened, how it happened, and why. Accountability, then, does not lay blame for or pin success to the person who is accountable, it only describes that person as being able to explain their actions or the actions of a group or business.
Responsibility
Responsibility is the idea of being completely in charge of something, that the person who is responsible for something is the root cause behind whether that thing succeeds, fails, lives, or dies. If a person is responsible for taking care of their favorite rose bush, that rose bush's fate, its liveliness, and its health now has a causality associated with that person. If it thrives, it was the responsibility of that person and can be attributed to that person's actions. If it dies, the responsibility also lies with that person.
This does necessarily mean that if the rose bush dies, the person will have to explain how or why the rose bush died. Responsibility merely says that blame (or praise) is assigned for whatever happens to the rosebush to one person, or a group of people. If the rose bush dies, it is the fault of that person or group, but they do not owe any explanation of how or why it happened.
One without the other?
As has been hinted, it is possible to have responsibility without accountability, or accountability without responsibility, though the two are often conflated into one larger meaning. The distinction between the two, however nuanced, still exists and can be seen heavily in the labyrinthine worlds of complicated legalese and business law.
One of the most pulled upon examples of accountability without responsibility are CEOs of major corporations. It is often assumed that CEOs are both accountable and responsible for the performance of their companies, evidenced by fat cheques cut for good years and the quick canning of executives when they underperform. However, Kenneth Lay, the notorious CEO of energy giant Enron during its 2001 bankruptcy, claimed that his position as chief executive left him accountable for the firm's actions - he was on hand to explain why Enron was falling apart - but he was not responsible for the fraud committed.
If Lay, in a purely hypothetical, wanted to claim responsibility but abdicate accountability, he would have eaten the Enron and headed to prison for the company's fraud without a word. This would have left the public and stockholders with justice for the crimes committed there, but oddly unfulfilled without an explanation of why or how it happened. The conviction of Lay proved that accountability and responsibility, while differentiated, often occupy the same place.