Guide overview
The essential idea
INDFMPIR is the ratio of reported family income to the applicable federal poverty guideline. In DEMO_L, 9,892 of 11,933 interviewed records have a released value and 2,041 are missing. The resulting 17.1 percent missing fraction is an unweighted file calculation. It is large enough that automatic complete-case exclusion can change the analytical sample and potentially its composition.
Practical framework
What to apply
9,892 available values
What does an observed INDFMPIR value represent?
- INDFMPIR divides annual family or individual income by the poverty guideline applicable to survey year, family size, and location.
- Observed values are available for 82.9 percent of interviewed DEMO_L records as an unweighted file ratio.
- Some incomes were reported exactly; others were assigned the midpoint of a selected income range.
- The measure is a ratio, not household income in dollars and not a direct measure of wealth.
2,041 missing values
Why should the 17.1 percent missing fraction be examined?
- INDFMPIR is missing for 2,041 of the 11,933 interviewed records in the public codebook frequencies.
- NCHS did not compute the ratio when the required income detail was unavailable or income data were missing.
- Excluding these records can reduce precision and alter the distribution of age, race and Hispanic origin, health status, or other covariates.
- The direction and importance of resulting bias cannot be inferred from the missing count alone.
Values at 5.00 are top-coded
What does the maximum public-use value mean?
- Values at or above 5.00 are released as 5.00 because of disclosure concerns.
- The codebook reports 2,149 records at the released value of 5.00.
- A value of 5.00 therefore means 5.00 or greater, not an exact ratio of 5.00.
- Modeling choices should respect this upper censoring and the study's scientific purpose.
Report the decision trail
How should INDFMPIR appear in an analysis and manuscript?
- Show the number and weighted proportion missing within the actual eligible analytical population.
- Compare key observed characteristics by INDFMPIR availability using survey-aware methods.
- Justify complete-case analysis, categorization, imputation, missing-indicator use, or sensitivity analyses.
- State the top-coding rule, chosen scale or categories, and any implications for interpretation.
Before you finish
A short quality review
- INDFMPIR is defined as a ratio to the applicable poverty guideline, not as dollar income.
- Missingness is quantified in the analysis-eligible population, not only the full file.
- Characteristics of records with and without INDFMPIR are examined where appropriate.
- The public-use top-code of 5.00 or greater is stated.
- The primary missing-data strategy is justified and sensitivity analyses are considered.
- Unweighted counts are distinguished from weighted estimates and population inference.
Missing is a result of the data-generating process. A complete-case model may be reasonable in some analyses, but it should be a documented scientific decision - not an unnoticed consequence of default software behavior.