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.

4variables selected

Praxis harmonization guidance available

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

4 variable assessments

ACD070

Compatible with harmonizationmoderate confidence

Questionnaire

In what country was {your/SP's} father born?

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

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

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

Praxis harmonization actions

Apply cycle-specific eligibility rules and restrict the pooled analytic population to a defensible common target population.
Verify merge grain, companion variables, and component-specific analytic guidance for the new file context.

Supporting CDC/NCHS evidence

Remove from study Variable history CDC source

ARXO2WD

Evidence developinglow confidence

Examination

OCCIPUT-TO-WALL DISTANCE IN CENTIMETERS

Source releases: 1
Available cycles: 2009-2010
Dataset: Arthritis Body Measures

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

AUDTYL05

Compatible with harmonizationmoderate confidence

Examination

Tympanometry-Left Ear, Measurement 5

Source releases: 7
Available cycles: 1999-2000 · 2001-2002 · 2003-2004 · 2005-2006 · 2007-2008 · 2009-2010 · 2011-2012
Dataset: Audiometry - Tympanometry

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 · 2003-2004 → 2005-2006 · 2005-2006 → 2007-2008 · 2007-2008 → 2009-2010 · 2009-2010 → 2011-2012

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.
Apply cycle-specific eligibility rules and restrict the pooled analytic population to a defensible common target population.

Supporting CDC/NCHS evidence

Remove from study Variable history CDC source

HRXHG

Evidence developinglow confidence

Laboratory

Total Hair Mercury as ug mercury/gram hair (ppm): MQL is Detection Limit (See Documentation for Definitions)

Source releases: 1
Available cycles: 1999-2000
Dataset: Mercury - Hair

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