Among adult height prediction methods, Khamis-Roche has become one of the most widely used non-invasive techniques over the last 30 years. The reason is simple: it doesn't require radiography (x-ray), needs only simple inputs from families, and delivers reasonable accuracy.
This article walks through how Khamis-Roche works, who it's suitable for, and its limitations.
How the method works
Harry Khamis and Alex Roche published their work in Pediatrics in 1994, deriving regression equations from the Fels Longitudinal Study. The general formula:
PAH = a(age, sex) + b(age, sex) × height + c(age, sex) × weight + d(age, sex) × MPH
A set of four coefficients (a, b, c, d) specific to the child's sex and decimal age multiply current height, weight, and mid-parental height to produce the predicted adult height.
Inputs
- Sex: male / female (different coefficients)
- Age: 4.0 to 17.5 yrs, in 0.5 yr increments
- Current height: cm
- Current weight: kg
- Mid-parental height (MPH): (father + mother) / 2
Output
A single point estimate (cm) + confidence interval (from residual standard deviation).
Accuracy: how much can I trust it?
Typical Khamis-Roche performance:
- Boys: mean standard error ≈ 5.6 cm
- Girls: mean standard error ≈ 4.3 cm
- 11-15 yrs (pubertal burst): median error 2.4-2.8 cm, 90th-percentile error 5.5-7.3 cm
So if you receive "182 cm" for a 12-yr-old boy:
- 68% likely between 176-188 cm
- 95% likely between 170-194 cm
This does not mean "exactly 182 cm." Like all scientific height prediction methods, the result is a probability distribution.
Strengths of Khamis-Roche
- No radiation: doesn't require hand-wrist x-ray
- Fast and cheap: can be entered by the family at home
- Field-compatible: widely used in bio-banding calculations for sports academies — reduces maturation bias in talent selection
- Wide age range: usable 4-17.5 yrs
Limitations
- Pubertal-timing insensitive: doesn't include BA, so error increases in very early or very late maturers
- Parental height must be accurate: self-report errors amplify the prediction error. Use measured values when possible.
- Pathological conditions must be excluded: endocrine disorders, chronic disease, undernutrition reduce method accuracy
- Population specificity: the Fels study was US-based; local validation for Turkey is recommended
Khamis-Roche for adolescent athletes
In adolescent football/basketball academies, Khamis-Roche has a special use case: %PAH (percent of adult height) calculation.
%PAH = (current height / predicted adult height) × 100
This metric shows how far along the child is in biological maturation. Two children of the same age — one at 95% PAH, another at 85% PAH — are at biologically different stages. Bio-banding tournaments use this metric to pair children by maturation level rather than chronological age.
Who shouldn't use Khamis-Roche?
- Children under 4 yrs (method not valid)
- Adolescents over 17.5 yrs (growth nearly complete, marginal value)
- Children with chronic growth disorders (clinical assessment is essential)
- When more precise prediction is needed (e.g., medical decision) — use Bayley-Pinneau or BoneXpert AHP
Conclusion
Khamis-Roche provides families with an accurate, realistic expectation framework. It should be used as a complement, not a sole decision-making tool, alongside pediatric specialist oversight.
Try our Khamis-Roche calculator (Premium) for Turkey-optimized projections. For free expectations, start with our Mid-Parental Height calculator.