I know that we could use linear regression to find impact of one independent variable on dependent variable and calculate its $r^2$.
What if this event is not continuous and happens only once and want to calculate its impact. How can I do this?
For example: say Uber is giving out $10 worth coupon to every users on Valentine's day. I want to find its impact:
- did it gather new users?
- did it gather users who were not recently using uber to use it regularly?
I can get result however there will be a lot of other variables that affect above numbers, how can I measure strength of $10 coupon on valentine's day?