Is There a Dissociation Between Deficit Subtypes in Word Reading and/or Spelling? A Longitudinal Study From Grade 1 to Grade 4 Across Orthographies

We investigated the stability of word reading and/or spelling deficits in children from Sweden (N = 170) and the U.S. (N = 452) from the end of Grade 1 to Grade 2 and from Grade 2 to Grade 4. Children were assessed for reading fluency and spelling accuracy and classified into subtypes with isolated reading deficits (RD), isolated spelling deficits (SD) or combined deficits (RSD). Stability was assessed using cross-tabulations and chi-square or Fisher's exact tests. The RSD subtype showed moderate to high stability across grades, whilst RD and especially SD were significantly less stable. These patterns held across orthographies. Although single-timepoint identification of isolated deficits may justify monitoring and support, our findings suggest limited predictive value for long-term persistence. This challenges prior assumptions about the stability of dissociative profiles and underscores that most children with literacy difficulties experience challenges in both the accuracy and efficiency of accessing phonological and orthographic representations. The results have implications for theoretical models of literacy development and for designing interventions targeting early reading and spelling difficulties.