We conducted a test-retest study (with 2 weeks between administrations) to examine NVLA stability.
We did not add verbal response sections given the availability of published assessments already accessible to students with verbal ability; NVLA was designed specifically for nonverbal responding.
For this measure, we conducted studies of fidelity of administration, interrater reliability, test-retest reliability, and internal reliability in the same manner as for NVLA. Mean fidelity of administration was 96.6%, with a range of 91.2% to 98.9%; interrater reliability was 96.4%, with a range of 92.5% to 99.2%.
The dependent variables in this study included the two measures we created, the NVLA and the ELSA.
The first series of ANOVAs examined the group interaction effects on the NVLA total score, CVR, PhonSk, and ELSA.
Three of the four interaction effects (NVLA total score, PhonSk, and ELSA) were statistically significant; Figure 1 illustrates the interactions.
John Beyer, of the NVLA, now known as Mediawatch, said yesterday: "History will record that she did perform an absolutely vital role in drawing attention to the media.
Whitehouse remained at the head of the NVLA until 1994.