Construct and incremental validity of dynamic assessment of decoding within and across domains

Dynamic assessment (DA) involves providing instruction and indexing students' responsiveness as a measure of learning potential. The purpose of this study was twofold: (a) to test whether a decoding DA measures early reading learning potential that is distinct from what can be assessed from static intelligence and decoding assessments; and (b) to examine the additive value of a decoding DA for explaining word reading and arithmetic performance beyond that which can be explained with static measures. First grade students (N = 112) were assessed on DA and measures of reading- and math-related predictors as well as domain-general learning indicators. Confirmatory factor analyses supported that DA measures early reading learning potential different from general intelligence and actual level of decoding. Structural equation models showed that DA was necessary in explaining only concurrent decoding skill beyond domain general learning measures and predictors of reading, suggesting that DA measures domain specific learning potential.