| Value | Category | 
|---|---|
| 0 | None | 
| 1 | Mediation | 
| 2 | Other relations | 
| 3 | Obtain the largest number of certificates | 
| 4 | Obtain a certificate from promoted university | 
| 5 | Certificate specialty | 
| 6 | Luck | 
| 7 | Living in a major city | 
| 8 | Experince | 
| 9 | Gender 'Female' | 
| 10 | Gender 'Male' | 
| 11 | Bribe | 
| 12 | Have a job | 
| 13 | Effeciency | 
| 14 | Behaviour and ethics | 
| 96 | Other factor | 
| 2147483625 | Don't know | 
| 2147483634 | Missing | 
| 2147483636 | Other | 
| 2147483639 | Refused | 
| Sysmiss |