Before revision:  However, due to the limited sample size in surveys and the dynamic topics over time , we instead conduct a large-scale social media study using Twitter data to portrait different groups who have positive/negative opinions about WFH.
After revision:  However, the findings are limited due to small sample size and the dynamic topics over time , we instead conduct a large-scale social media study using Twitter data to portrait different groups who have positive/negative opinions about WFH.