Table 3.
The 10 highest-ranked features for each of three feature extraction methods
| χ2 | Information Gain | Pearson Correlation |
|---|---|---|
| Frequency of undirected vocalizations (a9) | Integration of gaze and other behaviors during social overtures (b5)* | Frequency of spontaneous vocalization directed to others (a2)* |
| Frequency of spontaneous vocalization directed to others (a2)* | Amount of social overtures/maintenance of attention to examiner (b16a)* | Facial expressions directed to others (b4) |
| Pointing (a7) | Frequency of spontaneous vocalization directed to others (a2)* | Quality of social overtures (b15) |
| Intonation of vocalizations or verbalizations (a3) | Unusual eye contact (b1) | Pointing (a7) |
| Showing (b12)* | Quality of social overtures (b15) | Showing (b12)* |
| Amount of social overtures/maintenance of attention to examiner (b16a)* | Intonation of vocalizations or verbalizations (a3) | Integration of gaze and other behaviors during social overtures (b5)* |
| Requesting (b9) | Facial expressions directed to others (b4) | Unusual eye contact (b1) |
| Ignore (b8) | Overall quality of rapport (b18) | Overall quality of rapport (b18) |
| Spontaneous initiation of joint attention (b13) | Frequency of undirected vocalizations (a9) | Requesting (b9) |
| Integration of gaze and other behaviors during social overtures (b5)* | Showing (b12)* | Amount of social overtures/maintenance of attention to examiner (b16a)* |
*The features common to all three feature selection methods were a2, b5, b12, and b16a. Alphanumeric notations after each feature refer to ADOS-2 Toddler Module codes. (Two children over the age of 30 months were administered the Toddler Module.)