Table 5.
Age group comparisons for the top performing variables (by permutation feature importance).
| Variable | Type | Age 13-20 years (n=1014), meana (95% CI) | Age 21-54 years (n=643), meana (95% CI) | t statistic (df) | P value |
| Sentences per comments | Literary characteristics | −0.43 (−0.52, −0.35) | 0.37 (0.27, 0.46) | −12.31 (1489.89) | <.001 |
| Year account created | Summary statistics | 2.96 (2.79, 3.14) | 1.35 (1.10, 1.59) | 10.65 (1272.76) | <.001 |
| Proportion of user’s posts or comments in r/ teenagers | Subreddit frequencies | −3.49 (−3.67, −3.31) | −5.11 (−5.17, −5.05) | 16.69 (1208.10) | <.001 |
| 75th percentile subscriber count for subreddits user posted | Summary statistics | −0.14 (−0.23, −0.04) | −0.33 (−0.46, −0.20) | 2.41 (1276.15) | .02 |
| Average comment Coleman Liau Index | Literary characteristics | −0.25 (−0.34, −0.16) | 0.08 (−0.01, 0.17) | −5.06 (1571.31) | <.001 |
| Comment karma | Summary statistics | −0.19 (−0.25, −0.13) | 0.30 (0.22, 0.38) | −9.85 (1309.14) | <.001 |
| TF-IDFb weight for “school” | Term usage | −2.46 (−2.65, −2.27) | −2.63 (−2.86, −2.40) | 1.14 (1406.18) | .25 |
| Frequency of WWBPc 23-29 word set used | Term usage | −1.23 (−1.39, −1.08) | −0.05 (−0.20, 0.10) | −10.97 (1592.33) | <.001 |
| TF-IDF weight for “need” | Term usage | −1.58 (−1.75, −1.41) | −0.31 (−0.48, −0.15) | −10.48 (1577.27) | <.001 |
| Normalized count of WWBP 23-29 word set used | Term usage | −1.29 (−1.44, −1.14) | 0.04 (−0.11, 0.19) | −12.35 (1569.17) | <.001 |
| Proportion of comments posted in a thread user started | Summary statistics | −0.74 (−0.90, −0.57) | −1.41 (−1.62, −1.20) | 4.95 (1366.37) | <.001 |
| TF-IDF weight for “look like” | Term usage | −3.04 (−3.22, −2.86) | −1.84 (−2.08, −1.61) | −7.85 (1327.70) | <.001 |
| TF-IDF weight for “home” | Term usage | −3.45 (−3.62, −3.28) | −1.89 (−2.14, −1.65) | −10.24 (1252.67) | <.001 |
| TF-IDF weight for “totally” | Term usage | −4.23 (−4.37, −4.09) | −2.95 (−3.19, −2.71) | −8.92 (1092.36) | <.001 |
| Proportion of user’s posts or comments in r/news | Subreddit frequencies | −5.03 (−5.10, −4.97) | −4.29 (−4.48, −4.11) | −7.38 (810.43) | <.001 |
aQuantile transformed means.
bTF-IDF: term frequency–inverse document frequency.
cWorld Well-Being Project