| 0–3 years | | |
| Repeatedly very short: at least twice a length SDS <−2.5 | HSDS_1 <−2.5 and HSDS_2 <−2.5 AND 0.5⩽Age_2-Age_1<1 year AND (birth weight ⩾2500 g or, if no birth weight available, then first measurement within 0.1 year (5 weeks) with weight SDS⩾−2, and gestational age ⩾37 weeks (or not available)) | 1 |
| Extremely short: at least once a length SDS <−3 | HSDS <−3 AND (birth weight ⩾2500 g or if no birth weight available, then first measurement within 0.1 year (5 weeks) with weight SDS ⩾−2, and gestational age ⩾37 weeks (or not available)) | 2 |
| Combination of rules 1 and 2 | | 3 |
| 3–10 years | | |
| Short for target height | HSDS-THSDS <−2 AND HSDS <−2 | 1 |
| Very short: length SDS <−2.5 | HSDS <−2.5 | 2 |
| Height deflection | ΔHSDS <−1 AND HSDS <−2 | 3 |
| Combination of rules 1, 2 and 3 | | 4 |