The dependent or outcome variable is the risk of smoking one or more packs of cigarettes per day and is determined using the categorical variable, RSKPKCIG. This statistical analysis plan (SAP), in turn, results in two subpopulation analyses of proportions for each level of gender.
The example code provided below shows how to specify these variables correctly, using an individual year of the NSDUH PUF, and also indicates how to calculate the proportions, standard errors (SE), and confidence intervals of the risk of smoking one or more packs of cigarettes per day by gender. Users must consider the weighting, clustering, and stratification of the survey design to produce correct standard errors (and degrees of freedom). Using analysis weights is important to get the point estimates right.
Note that users should read the help document (of her/his respective statistical package) regarding how missing values are being handled if any exist in the analysis variables. The WR design is the default design, except in SPSS and Taylor series linearization is also the default method for variance estimation of them. SUDAAN, all survey procedures in SAS, Stata, R and the survey add-on module in SPSS can handle data from complex sampling designs. However, analysis variables can have missing values. There are no missing values in the variance estimation variables and final analysis weight, VESTR, VEREP and ANALWT_C. It is therefore considered that the complex survey method for NSDUH PUF is a single-stage stratified clustering design, where the clusters are sampled with replacement (WR). The NSDUH public-use file (PUF) includes the variance estimation variables (which were derived from the complex sample designs 2): variance estimation stratum (VESTR), variance estimation cluster replicates (VEREP) and final analysis weight (ANALWT_C).
National Survey on Drug Use and Health (NSDUH) 1 employs a multistage (stratified cluster) sample design for the selection of a representative sample from non-institutional members of United States households aged twelve and older.