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

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 study Variable history CDC source

ALQ121

Compatible with harmonizationmoderate confidence

Questionnaire

During the past 12 months, about how often did {you/SP} drink any type of alcoholic beverage? PROBE: How many days per week, per month, or per year did {you/SP} drink?

Source releases: 3
Available cycles: 2017-2018 · 2017-2020 · 2021-2023
Dataset: Alcohol Use

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: 2017-2018 → 2017-2020 · 2017-2020 → 2021-2023

Praxis harmonization actions

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