What are survey weights?

Analyzing Survey Data in R

Kelly McConville

Assistant Professor of Statistics

Survey data

• Have you ever found yourself analyzing a dataset that contained a column of weights and wondered what they were?

Survey weights

• What are survey weights?
  • They are the result of using a complex sampling design to select a sample from a population.
  • Roughly, the survey weight translates to the number of units in the population that a sampled unit represents.
    • First weight in BLS sample = 25,985 households
    • Second weight in BLS sample = 6,581 households
• How do survey weights impact my analyses?

Survey estimation

• Survey data are commonly used to estimate a finite population quantity.

Survey estimation

• Estimate the average household income in the U.S.: $\mu = \frac{1}{N} \sum_{i \in U} y_i.$

Survey estimation

• Using a complex sampling design, take a sample, called $s$, of $n$ households.

Survey estimation

• Sample mean estimator: $\bar{y} = \frac{1}{n} \sum_{i \in s} y_i$.

Survey estimation

• Sample mean estimator: $\bar{y} = \frac{1}{n} \sum_{i \in s} y_i$

 

mean(ce$FINCBTAX)

62480

Survey estimation

• For sampled units, we have the values and survey weights.

• How do I incorporate the weights?

• How do the weights impact my estimates? My graphics? My models?

Let's practice!

Analyzing Survey Data in R