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Praxis Data Lab

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

AAXFLTYP
Evidence developinglow confidence

Laboratory

Type of Floor Covering

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 studyVariable historyCDC source
ETHNICTY
Compatible with harmonizationmoderate confidence

Laboratory

Ethnicity - Recode

Source releases
8
Available cycles
2005-2006 · 2005-2006 · 2005-2006 · 2005-2006 · 2007-2008 · 2007-2008 · 2007-2008 · 2007-2008
Dataset
Polychlorinated dibenzo-p-dioxins (PCDDs), Dibenzofurans (PCDFs) & Coplanar Polychlorinated Biphenyls (cPCBs) - Pooled Samples

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: 2005-2006 → 2007-2008

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 studyVariable historyCDC source