| Explanatory Variables | Conditional | With Instrumental Variables* |
| p.e s.e | p.e s.e | |
| Past Behaviour* | −0.30 0.1 | −0.03 0.2 |
| Hours spend alone | ||
| up to 3 hours | 0.07 0.13 | 0.11 0.18 |
| 3 - 9 hours | −0.38 0.13 | −0.37 0.14 |
| 9+ hours | 0.00 | 0.00 |
| Has close relatives | ||
| yes | 0.00 | 0.00 |
| no | −0.32 0.13 | −0.32 0.13 |
| Subjective variables | ||
| Presence of friends** | ||
| yes | 0.00 | 0.00 |
| no | 0.43 0.15 | 0.22 0.64 |