Understanding Z-Scores
The WHO Child Growth Standards provide the international benchmark for assessing child growth. Z-scores quantify exactly how far a child's measurement deviates from the median of the reference population.
| Z-Score Range | Classification | Interpretation |
|---|---|---|
| < -3 | Severely underweight/stunted/wasted | Severe malnutrition, requires immediate intervention |
| -3 to -2 | Moderately underweight/stunted/wasted | Moderate malnutrition, requires intervention |
| -2 to +2 | Normal | Within expected range for healthy children |
| > +2 | Above normal | May indicate overweight/obesity or tall stature |
Which Score Matters?
- WAZ (Weight-for-Age): General indicator of underweight; doesn't distinguish chronic vs acute
- HAZ (Height-for-Age): Indicator of stunting (chronic undernutrition)
- WHZ (Weight-for-Height): Indicator of wasting (acute undernutrition)
- BMI-for-Age: Used for overweight/obesity assessment
Important note: WHZ is the preferred indicator for wasting in emergency nutrition surveys. HAZ reflects long-term nutritional status. Both are more informative than WAZ alone.
Track your child's growth over time
GrowChart automatically plots measurements on WHO charts and shows the trajectory.