Psychologists assess dyslexia by testing verbal and literacy skills against information-processing skills and other measures of intelligence that are deemed "non-verbal" (though people often use words in their minds to tackle the tests). If verbal scores are a lot lower than overall IQ, and there is not some other cause, such as illness, the outcome is likely to be described as "consistent with" specific learning difficulties (dyslexia).
The Dyslexia Screener allows schools to begin this assessment through computerised tests of ability, information processing, and reading and spelling. The tests are easy to use and would be accessible to children struggling with early reading, as well as adults. They have good scope for identifying high ability, but the authors should have given guidance for visual factors, that may affect performance, particularly on their test of visual search.
The computer manages the data analysis efficiently, and the manual is very clearly written. The tests are not the same as those used by psychologists and so would not satisfy some parents. Nevertheless, the screener has the potential to save time and money and deserves serious consideration, particularly in areas where assessments are hard to obtain and parents cannot afford private fees.