Spanish Rett Syndrome Behavior Questionnaire: ICC 0.907
A 2026 Spanish Rett Syndrome Behavior Questionnaire validation preprint found strong test-retest reliability across 51 caregivers, including an intraclass correlation coefficient of 0.907 and a 31-person short-interval subset with Pearson r2 = 0.8663.1 The result supports Spanish-language research access, but it is linguistic validation rather than proof that the scale diagnoses Rett syndrome or measures …