The IQ-discrepancy definition for problematic readers (e.g. dyslexia) is subpar as they often show average scores on measures of word level skills. Intelligence tests do not differentiate the atypically achieving children from a group of typically achieving children when it comes to reading performance. Early reading difficulties in most beginning readers are caused primarily by experiential and instructional deficits rather than basic deficits in reading-related cognitive abilities.

Most struggling readers can become average-level readers if they are provided with effective intervention. Those who continue to experience difficulties mat require more intensive or more individualized instruction to achieve this level.

The three-tier model of remedial intervention consists of three sequentially ordered intervention strategies:

1. Tier 1
   This includes assessment and possible modification of the language programme to ensure that literacy instruction provided by the teacher is addressing the individual needs of all children in the classroom, including those who are experiencing early literacy difficulties.
2. Tier 2
   This involves secondary intervention (i.e. small group) for children whose literacy difficulties are not resolved by appropriate adjustments.
3. Tier 3
   This includes more intensive intervention (e.g. daily one-to-one tutoring) for children who continue to experience literacy difficulties.

All strategies rely on continuous monitoring of student progress. This determines the eligibility for a given tier. The idea is that when a child does not respond to any given intervention, the child moves up a tier.

Using response to intervention (RTI) may be useful to identify at-risk children for literacy difficulties. This includes early screening and subsequent response to an intervention determines whether these children should be classified as continued at-risk or no risk.

The kindergarten intervention (i.e. small group supplementary intervention or other instructional activities) is effective in improving literacy skills of children judged to be at-risk for early reading difficulties at the beginning of kindergarten. Poor readers who had difficulty consolidating intervention-based gains at the end of first grade were more likely to be at-risk for continued reading difficulties.

Children at risk for early and long-term reading difficulties can and should be identified at the beginning of kindergarten. Their difficulties can be prevented if they are provided with supplementary remedial services. Children with persistent reading difficulties (i.e. after intervention) appear to have a weak cognitive profile. Identification of at-risk children or poor readers was more accurate with time and especially when losses over the summer period were taken into account.

Response to kindergarten intervention predicted performance on measures of response to first grade intervention. The response to first grade intervention predicts follow-up measures and this thus justifies using RTI. RTI is a good way of identifying children who may be at risk for early and long-term reading difficulties. RTI is a better way of identification between continued-risk and no-longer-at-risk children (i.e. after initial screening for at-risk children) than other psychometric measures.

Early identification has some risk for false positives but not screening and having false negatives or not identifying at-risk children at all is a bigger problem. Early screening also allows to partially determine the degree of risk which allows for tailoring instruction to individual needs.

The majority of the at-risk children will achieve average-levels of reading with a small group supplementary intervention provided throughout kindergarten. Some will require more intensive and more individualized intervention to achieve grade level reading skills. There are some children who will experience persistent reading difficulties despite a more individualized and intensive intervention and they require additional assistance. These children with persisting difficulties may be impaired by basic deficits in reading-related cognitive abilities. RTI measures are more effective than initial screening measures or IQ tests to distinguish at-risk children who will obtain average performance with a small group supplementary intervention and children who require more intensive and individualized intervention.