Examining the genetic and environmental associations among spelling, reading fluency, reading comprehension and a high stakes reading test in a combined sample of third and fourth grade students

•Our study extends investigations of the relations between reading fluency, spelling and reading comprehension skills•This investigation is the first to examine the etiological influences on reading fluency, spelling and reading comprehension•Our investigation explores the underlying etiology of state standardized assessments aligned with the Common Core initiative•Our study includes a large and diverse sample of twins

The present study is an examination of the genetic and environmental effects on the associations among reading fluency, spelling and earlier reading comprehension on a later reading comprehension outcome (FCAT) in a combined sample of 3rd and 4th grade students using data from the 2011–2012 school year of the Florida Twin project on Reading (Taylor et al., 2013). A genetically sensitive model was applied to the data with results indicating a common genetic component among all four measures, along with shared and non-shared environmental influences common between reading fluency, spelling and FCAT.