Praxis Data Lab · Study Builder

Build your NHANES study with harmonization intelligence.

Combine variables from the indexed Continuous NHANES catalog, choose the cycles you need, and see how Praxis connects source history, methods, cycle boundaries, and cross-code lineage into a study-specific harmonization view.

1variable selected

Praxis harmonization guidance available

Praxis found harmonization conditions for this study and has surfaced them below with the supporting source evidence.

1 variable assessment

AGD050

Evidence developinglow confidence

Questionnaire

How old {were you/was SP} when {you were/s/he was} first told {you/he/she} had allergies?

Source releases: 1
Available cycles: 2005-2006
Dataset: Allergy

No normalized longitudinal change evidence is available for this variable. Absence of events must not be interpreted as proof of cross-cycle equivalence.

Evidence provenance: Praxis automated inference from indexed CDC/NCHS evidence

Remove from study Variable history CDC source