Page Last Updated: October 10, 2025
Growth🔗
ph_ch_anthroZ-Scores Excluded From Current Release
Because dates of birth are jittered and calculated chronologic and adjusted ages are ±6 days, we do not provide z-scores in the current data release. Further, we do NOT recommend calculating z-scores using V02 data. Caution is recommended when calculating Z-scores using data from subsequent visits. Future data releases will have z-scores calculated with age in days for investigators wanting to compare to normative growth metrics.
Range Checks for Growth
Please note that range checks for Growth (ph_ch_anthro) were implemented in the database on 7/1/2024 and so are not reflected in data included in the first data release. Extreme out-of-range values were excluded (converted to 'n/a'), but some outliers are possible. Valid values for Growth fields are documented here under Exclusion Criteria for the current release and provided below for quick reference:
- Length (
len_001_i_03): min 30 / max 130 (cm) - Weight (
wei_001_i_03): min 0.5 / max 30 (kg) - Head Circumference (
head_001_i_03): min 25 / max 55 (cm)
Administration & Quality Control🔗
| Child Specific | Yes |
| Respondent | NA |
| Administration | HBCD Study Staff, in person. |
| Visits | V02, V03, V04, V06, V08 |
| Completion Time | 5 min |
| Quality Control | Monitor data dashboard for variable missingness, possible coding errors, scoring verification when needed, and data consistency. |
Instrument Details🔗
Growth is a standard direct measure of child growth, including height or length (in cm), weight (in kg), and head circumference (cm). In older children, it will also include abdominal circumference (cm). Because of the jittered date of birth we do not recommend using raw data to calculate age based z-score for growth measurements for V02 data. Children in this window are between 0-30 days older than their estimated due date thus the jittering of age may introduce error.