Final answer:
Individuals who possess a strong belief in their ability to achieve their goals, known as self-efficacy, are typically more successful in accomplishing what they set out to do. They set appropriate goals and actively work towards them, starting early and maintaining a positive outlook even in long-term pursuits.
Step-by-step explanation:
The individuals most likely to accomplish what they set out to do are indeed typically those who believe that they can achieve that goal, aligning with the concept of self-efficacy. This belief in one's own abilities is fundamental to setting achievable and appropriate goals, as well as devising a plan to succeed in these goals (A: Achievable and appropriate). Furthermore, possessing high self-efficacy can drive a person to pursue success and to start working towards their goals sooner, which is crucial according to the principle that the sooner one starts, the more likely they are to succeed (R: Relevant and result-based)
Those with lower self-efficacy, or pessimists, may find it more challenging to embark on long-term, ambitious undertakings (This is harder for pessimists to pull off). However, an individual's belief in their ability to control outcomes (c. the belief that we control our own outcomes) can be just as influential in achieving success as the actual steps taken toward that end.
It's therefore accurate to assert that a person's conviction in their capability to realize their goals is a significant enabler for success.