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

BMDBMIC

Compatible with harmonizationmoderate confidence

Examination

BMI Category - Children/Adolescents

Source releases: 5
Available cycles: 2011-2012 · 2013-2014 · 2015-2016 · 2017-2020 · 2021-2023
Dataset: Body Measures

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: automated-difference · source-derived

Relevant boundaries: 2011-2012 → 2013-2014 · 2013-2014 → 2015-2016 · 2015-2016 → 2017-2020 · 2017-2020 → 2021-2023

Praxis harmonization actions

Confirm that the construct and coding are unchanged before pooling or recoding.
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

BPD058

Compatible with harmonizationmoderate confidence

Questionnaire

How often {did you check your/did SP check his/her} blood pressure at home during the last 12 months?

Source releases: 3
Available cycles: 2009-2010 · 2011-2012 · 2013-2014
Dataset: Blood Pressure & Cholesterol