**Codebook**
HLx = položky HLSAC, prvá administrácia [HLSAC items, first administration]
RHLx = položky HLSAC, retest [HLSAC items, retest]
ID3 = trieda [class identifier]
M1 = pohlavie [gender];
1 = chlapec [male], 2 = dievča [female]
M2 = ročník [grade];
1 = 7. ročník [7. grade], 2 = 9. ročník [9. grade]
M3 = mesiac narodenia [month of birth]
M4 = rok narodenia [year of birth]