Early prediction of individual growth in reading

Seventy four boys with reading disabilities and a matched control group of normal readers were followed during their compulsory schooling (to grade 9) . Word decoding performance was assessed with the Wordchains test on three occasions. For each student a linear growth function was estimated. The slo pe parameter was used as the dependent variable in a multiple regression an alysis with a large number of explanatory factors from grades 2 and 3 inclu ding phonological skills, reading and spelling, non-verbal intelligence, mo tor skills, eye movements, teacher ratings of school behaviour and parents' education. The proportion of variance in growth explained for the reading disabled boys amounted to 25%, the most powerful predictors being early rea ding performance and non-verbal intelligence. More surprisingly, neither te acher ratings nor family background gave useful predictive information. For the control group none of the independent variables explained the variance of growth in reading.