From the report one might find FAQ table interesting.
The illiteracy also covers being able to do math. If people only depend of text to speech and speech recognition formats, they lose their critical thinking skills.
While the report does not actually say that one can make the inference. This also explains the heavy handed use by the democrat party being able to censor what they call disinformation. Why? Because the people who are falling under the 6th grade bench mark in reading and math, essentially are not able to think critically. Follow the experts, follow the science all those catch phrases will make people easy to manipulate.
https://nces.ed.gov/surveys/piaac/state-county-estimates.asp#4
A teacher in an inner city school reported that little Asian kids came to school already knowing math although they are poor at reading and writing. Math and language arts only weakly depend on each other.
As for critical thinking, consider that in this state jurors are not permitted to read transcripts of testimony while deliberating. Instead, if they want to refer back to what was presented in court, they can request that the clerk read back portions of the transcript. So critical thinking can presumably be done using only verbal communication.
Universal literacy was originally promoted so that Protestants could read the Bible in the vernacular, and so that non-commissioned officers could read and write orders.
the people who are falling under the 6th grade bench mark in reading and math, essentially are not able to think critically.
***That is probably true. Critical thinking has become a rare capability. You can even see this on FR.