Good question. And due to “no child left behind” more and more students with IQs in the 80s are being referred for special education evaluations because they are struggling to keep up with their class. Typically, due to regression toward the mean, a student with an IQ of 80 would be expected to have a reading achievement standard score near or slightly above 80. If the IQ score is considered valid and the reading score is within that range, it is unlikely that the reading difficulty is due to a learning disability and is much more likely a function of the relatively low IQ. If the reading score is significantly lower than 80 (at that level significant may be 12-15 points) then it is likely that there is something fairly significant which is interfering with the acquisition of reading skills (such as a learning disability). At that point I would look broadly at the subtests and/or subscales of the IQ test to see if there is any pattern of specific information processing strength or weakness that might account for the reading difficulties. A true reading disability is typically related to difficulty processing either verbal or language-based information or detailed sequential information. So I would be looking closely at the student’s performance on all verbal subtests as well as subtests involving memory and sequencing (such as digit span and coding). Processing speed difficulties would also tend to impact reading along with other academic areas. If there is significant subtest scatter, I would also wonder if the Full Scale IQ score is an accurate reflection of the student’s true intellectual abilities (which may cause me to reevaluate the significance of the discrepancy between IQ and achievement). If analysis of the IQ test is not indicative of cognitive processing issues consistent with a reading disability then I would keep searching until I found additional evidence of cognitive processing difficulty or another explanation to account for the relatively significant underachievement.