Judging ability is tricky. Sometimes ability is an innate, personal trait, and other times it is a by-product of education or experience. In considering abilities necessary to perform a job, be sure to separate abilities from educational requirements when applicable.
In some instances, ability is related to education, and only after a certain amount of education does a person have the ability to perform certain tasks. Consider lawyers and accountants. Generally, they must have an advanced degree and be certified in the state where they practice. Their ability to perform their duties is a by-product of their education and certification.
But sometimes, ability is not related to a specific educational attainment. Some people are natural-born communicators, for instance, and they tend to deal with people well. They can communicate easily and can develop a sense of rapport with people that makes people want to deal with them. This is a wonderful quality in a salesperson or an office receptionist. It is not something that is necessarily a product of education.
When you consider abilities, look not only at those that come from education, but at those that are desirable or necessary personal traits for that job, such as being able to communicate well with others.