I am conducting a cross-sectional study of 99 UK firms in 2017. I aim to find a positive/negative relationship between a board characteristic and performance variables (i.e. ROA, ROA, EBITDA, Tobin's Q) while controlling for firm and board characteristics. Previous studies use panel data methodology but due to data limitations, I only have values for my main independent variable for 2017 hence the choice of a cross-sectional study. I want to explore the differences between performance across various industries as well. Can anyone point me to a method and code suitable for this type of study and small sample size?