| Variable | Frequency | Valid percentage |
| Conference | 12 | 5.4 |
| Colleagues | 103 | 46.6 |
| Professional journals | 17 | 7.7 |
| Books | 42 | 19.0 |
| NSP newsletter | 11 | 5.0 |
| NSP website | 1 | 0.5 |
| In-service training | 24 | 10.9 |
| Others (internet) | 10 | 4.5 |
| Non | 1 | 0.5 |
| Total | 221 | 100 |