There is a theory of reading called the Simple View. This theory states that reading is the product of the ability to decode (read words) and the ability to understand the language of the text. This is certainly a simple way to think of reading, but learning to decode and understand the language of text is not easy. Many people struggle with at least one of these skills and some struggle with both of these skills.

Any difficulty in decoding (the ability to read novel words) will affect reading and, as a result, all academic areas. Similarly, any difficulty in understanding the written text will affect reading comprehension in all academic areas.  Both learning to decode and comprehend text are complex skills.  Thus, the Simple View of reading states clearly the two main ingredients to reading, but these ingredients are complex and many students require direct, explicit instruction to gain these skills.