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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.

6variables selected
Praxis harmonization guidance available

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

6 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
ACD040
Compatible with harmonizationmoderate confidence

Questionnaire

What language(s) {do you/does SP} usually speak at home? Would you say...

Source releases
12
Available cycles
1999-2000 · 2001-2002 · 2003-2004 · 2005-2006 · 2007-2008 · 2009-2010 · 2011-2012 · 2013-2014 · 2015-2016 · 2017-2018 · 2017-2020 · 2021-2023
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 · 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 · 2011-2012 → 2013-2014 · 2013-2014 → 2015-2016 · 2015-2016 → 2017-2018 · 2017-2018 → 2017-2020 · 2017-2020 → 2021-2023

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.
  • Confirm that the construct and coding are unchanged before pooling or recoding.
Supporting CDC/NCHS evidence
Remove from studyVariable historyCDC 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 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
DCDINDEX
Compatible with harmonizationmoderate confidence

Laboratory

Source releases
3
Available cycles
1999-2000 · 2001-2002 · 2003-2004
Dataset
Lead - Dust

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

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
SIAPROXY
Compatible with harmonizationmoderate confidence

Demographics

Was a Proxy respondent used in conducting the Sample Person (SP) interview?

Source releases
9
Available cycles
2003-2004 · 2005-2006 · 2007-2008 · 2009-2010 · 2011-2012 · 2013-2014 · 2015-2016 · 2017-2018 · 2017-2020
Dataset
Demographic Variables & Sample Weights

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: 2003-2004 → 2005-2006 · 2005-2006 → 2007-2008 · 2007-2008 → 2009-2010 · 2009-2010 → 2011-2012 · 2011-2012 → 2013-2014 · 2013-2014 → 2015-2016 · 2015-2016 → 2017-2018 · 2017-2018 → 2017-2020

Praxis harmonization actions
  • Verify merge grain, companion variables, and component-specific analytic guidance for the new file context.
  • Select the weight appropriate to each cycle and subsample; when pooling cycles, construct the combined weight according to NHANES guidance rather than reusing a single-cycle weight unchanged.
Supporting CDC/NCHS evidence
Remove from studyVariable historyCDC source