Oh no, I very much do. I have a degree in psychology that requires being able to do statistical analysis for research.
You use a focus group to elicit qualitative, not quantitative, info from a targeted group in a study, not as the study itself. The issue is, it’s not meant for broad populations or for quantitative studies. Even then, the data is easily skewed by biases from the group themselves, the moderator, and the interpreter and shouldn’t be the only thing used.
Focus groups are meant for things like quality indicators, where you use a range of them in general analysis, which can help to triangulate where an issue is.
To properly employ a focus group, you would first need to poll an appropriate sample size of undecided voters then you target demographics within the sample to gain insight into why they answered their poll as they did.