Literacy is defined by government agencies as the ability function when reading, writing, preparing written documents, and working with basic numbers. Illiteracy, on the other hand, is essentially not being able to read or comprehend written communication. Functional illiteracy involves being able to read but at such a simple level, the person is considered under a basic skill level. This skill threshold in many jurisdictions is considered the 6th grade reading ability.
People with illiteracy range from extreme dysfunction to limited function. According to the "New England Journal of Medicine," 12 percent of the adult American population can't properly read a document at all. Twenty-two percent can function with basic reading but can't handle complex thinking. These limitations bar people in a number of different ways, depending on their ability to adapt, their life experience, and their daily need to read. For example, a plumber may not have a significant career demand to perform complex reading to do his job. On the other hand, a person who can't perform above a sixth-grade level of literacy is probably not going to be hired as a journalist. Such limitations force people into certain paths of life, discouraging them from others.
A community with a high rate of illiteracy also suffers as a group. Employers and companies cannot operate a workforce that has a significant literacy problem. If an employee can't understand instructions, processes, data or sensors, the employer can only use him for basic manual work. Such communities lack significant business development until someone can come in and boost the education level of the population.
Illiteracy has been found to affect both ongoing health maintenance as well as long-term growth and learning. In the short term, not being able to read and follow instructions can cause significant health problems in a patient expected to self-medicate, particularly with prescriptions and outpatient treatment. In short, she won't follow instructions because she can't read them. The result could be recurrence of a chronic health problem. In the long term, illiteracy has been found to limit a person's ability to develop brain capacity. Motor skills, cognitive skills, verbal development and tool control all suffer.