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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.

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

AADFLSP
Evidence developinglow confidence

Laboratory

Floor Space Vacuumed (square inches)

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
ARDLFTL
Evidence developinglow confidence

Examination

THE DISTANCE IN CM BETWEEN THE TWO INDICATOR MARKS PLACED ON THE LOWER BACK WHEN THE EXAMINEE BENDS FORWARD IN FLEXION MINUS 10 CM (10 CM IS THE BASELINE DISTANCE BETWEEN THE INDICATOR MARKS WHEN THE EXAMINEE STANDS UPRIGHT)

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 studyVariable historyCDC 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 studyVariable historyCDC source
AUDTYL32
Compatible with harmonizationmoderate confidence

Examination

Tympanometry-Left Ear, Measurement 32

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 studyVariable historyCDC source