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

AAXBDMAT

Evidence developinglow confidence

Laboratory

Impermeable Mattress Cover

Source releases: 1
Available cycles: 2005-2006
Dataset: Allergens - Household Dust

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

ACD080

Compatible with harmonizationmoderate confidence

Questionnaire

In what country was {your/SP's} mother 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

AUQ330

Compatible with harmonizationmoderate confidence

Questionnaire

These next questions are about noise exposure {you/SP} may have had at work. {Have you/Has SP} ever had a job, or combination of jobs where {you were/s/he was} exposed to loud sounds or noise for 4 or more hours a day, several days a week? Loud means so loud that {you/s/he} must speak in a raised voice to be heard.

Source releases: 3
Available cycles: 2011-2012 · 2017-2018 · 2017-2020
Dataset: Audiometry

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 → 2017-2018 · 2017-2018 → 2017-2020

Praxis harmonization actions

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