Planned missing data in early literacy interventions: A replication study with an additional gold standard.

ABSTRACT

INTRODUCTION: In a digital early literacy intervention RCT, children born late preterm fell behind peers when in a control condition, but outperformed them when assigned to the intervention. Results did however not replicate previous findings. Replication is often complicated by resource quality. Gold Standard measures are generally time-intensive and costly, while they closely align with, and are more sensitive to changes in, early literacy and language performance. A planned missing data approach, leaving these gold standard measures incomplete, might aid in addressing the origin(s) of non-replication. METHODS: Participants after consent were 695 p Dutch primary school pupils of normal and late preterm birth. The high-quality measures, in additional to simpler but complete measures, were intentionally administered to a random subsample of children. Five definitions of gold standard alignment were evaluated. RESULTS: Two out of five gold standard levels improved precision compared to the original results. The lowest gold standard level did not lead to improvement precision was actually diminished. In two gold standard definitions, an alphabetical factor and a writing-only factor the model estimates were comparable to the original results. Only the most precise definition of the gold standard level replicated the original results. CONCLUSION: Gold standard measures could only be used to improve model efficiency in RCT-designs under sufficiently high convergent validity.