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.

2variables selected

Praxis harmonization guidance available

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

2 variable assessments

DCDINDEX

Compatible with harmonizationmoderate confidence

Laboratory

Source releases: 3
Available cycles: 1999-2000 · 2001-2002 · 2003-2004
Dataset: Lead - Dust

No blocking method discontinuity is identified inside the selected cycle span, but one or more longitudinal changes require explicit harmonization conditions before pooling.

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

Evidence signals: source-derived · automated-difference

Relevant boundaries: 1999-2000 → 2001-2002 · 2001-2002 → 2003-2004

Praxis harmonization actions

Verify merge grain, companion variables, and component-specific analytic guidance for the new file context.
Review the adjacent codebooks/methods. Keep this boundary as documentation variation unless source evidence confirms a substantive method or instrument change.

Supporting CDC/NCHS evidence

Remove from study Variable history CDC source

RIDEXAGM

Compatible with harmonizationmoderate confidence

Demographics

Age in months of the participant at the time of examination. Reported for persons aged 19 years or younger at the time of examination.

Source releases: 5
Available cycles: 2011-2012 · 2013-2014 · 2015-2016 · 2017-2018 · 2021-2023
Dataset: Demographic Variables & Sample Weights