Immigration

Methodology note

Focaldata specialises in mapping opinion poll data onto smaller geographic areas, using a technique known as MRP, or Multilevel Regression with Post-stratification. For this study we collected data from 10,009 respondents between 12th and 16th December 2022 using Focaldata’s online platform.

While this does not yield enough observations in individual constituencies to treat the data as separate constituency polls, we can look for patterns in responses across constituencies that have similar characteristics, and then work out the implications of those patterns for each constituency.

This technique of “multilevel regression and post-stratification” or MRP is the same approach used by Focaldata to predict Vote Intention in Westminster constituencies. Focaldata’s MRP model uses age, gender, education, working status, VoteGE2019, referendum vote, religion and housing tenure as individual-level predictors in the model. It also uses population density, % born in the UK, and % gross income median. We used a Bayesian exploded logit model, which is fit using Hamiltonian Monte Carlo with the open-source software Stan.

NOTE: These estimates include the 632 constituencies in England, Scotland and Wales, but not the 18 constituencies in Northern Ireland.