Reading ability is very difficult to assess accurately. In the communicative competence model, a student's reading level is the level at which that student is able to use reading to accomplish communication goals. This means that assessment of reading ability needs to be correlated with purposes for reading.
The ability to read proficiently is a fundamental skill that affects the learning experiences and school performance of children and adolescents. Students who are competent readers, as measured by their performance on reading tests, are more likely to perform well in other subjects, such as math and science. Children who struggle with reading and reading comprehension also often have deficits in spoken language. Students with reading difficulties are much less likely to be academically engaged. Reading achievement predicts the likelihood of graduating from high school and attending college.
A student's performance when reading aloud is not a reliable indicator of that student's reading ability. A student who is perfectly capable of understanding a given text when reading it silently may stumble when asked to combine comprehension with word recognition and speaking ability in the way that reading aloud requires.
Reading skills also influence students’ well-being as adults. Adults with poor literacy skills find it difficult to function in society, because many basic decision-making skills require reading proficiency. People who are not able to fill out an application because of limited reading or writing skills are likely to have difficulty finding a job or accessing social services. Strong reading skills protect against unemployment in early adulthood. Adults with limited reading abilities are likely to have children with limited reading abilities.