Purpose of the Questionnaire (Scale)

The primary purpose of the EDTD-15 (Early Detection Test for Dyslexia – 15) is to identify risk factors for dyslexia in children aged 4–6 years. The tool is intended for preschool educators, psychologists, and special education professionals, and evaluates areas such as phonological awareness, visuomotor skills, working memory, and sequence processing. It was developed by Stavrou and Zakopoulou in 2020 and is widely used in Greek educational research.

Questionnaire (Scale) Analysis

The tool, created by L. Stavrou and V. Zakopoulou in 2020, consists of 15 subtests, grouped into 5 subscales:
Phonological Processing (4 subtests)
Visuomotor Coordination (3 subtests)
Memory and Sequences (4 subtests)
Spatiotemporal Concepts (2 subtests)
Behavioral Observations (2 subtests)
The response format is based on a 4-point Likert scale, ranging from 0 to 3.

Scoring of Questions

Each subtest is scored from 0 (no difficulty) to 3 (significant difficulty), and the total score ranges from 0 to 45 points:
0–10: low risk
11–20: moderate risk
21+: high risk for dyslexia
Behavioral parameters are assessed separately on a 1–5 scale for attention span and task persistence.

Statistical Analysis

The total scale ranges from 0 to 45, with higher scores indicating greater risk. The subscales are weighted as follows:
Phonological processing: 35%
Visuomotor coordination: 25%
Memory: 25%
Spatiotemporal concepts: 15%
Clinical concern is indicated by scores above the 85th percentile. For instance, a score of 18 corresponding to the 75th percentile suggests the need for follow-up.

Validity of the Questionnaire (Scale)

Construct validity was confirmed through factor analysis with α = 0.89.
Criterion validity indicates 82% accuracy in predicting reading difficulties in 1st grade, and there is a strong correlation with the DST-J tool (r = 0.76).

Reliability of the Questionnaire (Scale)

Overall internal consistency is high, with α = 0.91.
Test-retest reliability over a 4-week interval showed r = 0.86, and inter-rater agreement had a value of κ = 0.79.

Bibliography

Greek references include:
Stavrou & Zakopoulou (2020), Early Detection of Dyslexia, published by Grigoris
Papadopoulou (2022), Greek Preschool Assessment Norms, published in the Scientific Yearbook of Psychology
International references:
Snowling (2019), Dyslexia: A Very Short Introduction, Oxford University Press
Vellutino (2004), article in the Journal of Educational Psychology

Keywords

Dyslexia prediction, preschool assessment, phonological awareness, Greek language test, early intervention, psychometric tool, learning difficulties.