To ensure the reliability of any findings, the dependent
measures (reading and spelling tests) were selected because
they have high test–retest reliability that reduces the likelihood
of regression to the mean. Therefore, pre- and postintervention
testing was conducted in reading and spelling
using the Group Reading Test (GRT) II [Granada Learning
(GLassessment)] and the SingleWord SpellingTest (SWST)
(GLassessment). These tests have 90% confidence intervals.
Results are reported in standardised scores because standardised
scores enable test-takers to be compared with a large,
nationally representative sample and are, therefore, more
useful measures than raw scores or reading ages.