Overview
The Trafalgar Group is an opinion polling and survey company founded by Robert Cahaly and based in Atlanta, Georgia. It first publicly released polls in 2016. Trafalgar has been questioned for its methodology and for an apparent bias towards the Republican Party.
Notably, Trafalgar successfully predicted the result of the 2016 U.S. presidential election. Although they incorrectly predicted the result of the 2020 U.S. presidential election for Trump in several states, their state polling margins were considered as some of the most accurate that cycle.
Trafalgar's polls for the 2022 midterms were inaccurate, predicting Republican wins or close races in multiple states where Republicans ended up losing by significant margins.
Method
Trafalgar Group adjusts its polls for a "social desirability bias" effect, the hypothesized tendency of some voters to calibrate their responses to polls towards what they believe the survey taker would like to hear. It does this by not only asking respondents how they plan to vote, but also how they think their neighbors might vote.
From Wikipedia (CC BY-SA 4.0).