Weighting and Its Consequences

Variance Reduction in Discrete Outcomes and Its Implications for Survey Aggregation

Mark Rieke

May 15, 2025

Disclaimer

The views and opinions expressed in this presentation are wholly my own and do not necessarily represent that of my employer, Game Data Pros, Inc (GDP).

Outline

  • Setting the Stage
  • Recreating Results
  • Extending the Example
  • Adjustments for Aggregators

Setting the Stage

Setting the Stage: About Me

Setting the Stage: About Me

Setting the Stage: Pennsylvania Polling

date sample_size margin
September 24 760 -
September 24 582 +3.1%
September 23 601 +2.2%
September 23 384 -
September 22 644 -
September 20 768 -
September 20 760 +1.1%
September 19 1,020 -
September 19 432 -
September 19 752 +2.1%

Setting the Stage: Pennsylvania Polling

Recreating Results

Recreating Results

Recreating Results

group group_mean population p_respond
A 400 60% 10%
B 800 20% 5%
C 700 10% 3%
D 600 10% 1%
  • True population mean: 530
  • Responses sampled from \(\mathcal{N}(\mu_g,50)\)
  • Simple population weighting strategy: \(w_g = \frac{P_g}{\left(\frac{N_g}{\sum_g N_g} \right)}\)

Recreating Results

Extending the Example

Extending the Example

  • Little and Vartivarian demonstrate the effect of weighting with a continuous outcome.
  • A broad class of survey results are discrete outcomes.
  • How do these effects hold up in the discrete case?

Extending the Example

group group_mean population p_respond
A 3% 50% 5%
B 97% 50% 7%
  • True population mean: 50%
  • Responses sampled from \(\text{Bernoulli}(\theta_g)\)
  • Simple population weighting strategy: \(w_g = \frac{P_g}{\left(\frac{N_g}{\sum_g N_g} \right)}\)

Extending the Example