Dear all

For my master thesis I am trying to get a count of all green patents per state over the years.

The plan was to link Rawlocation with Rawinventor in a first step to get the states of the inventors. Afterwards link the joined file to Applications to get the date of the application and so on.
 

To get the states, I have encoded the variable "state" in the datafile Rawlocation.tsv as factor. However, for most of the rows there is no entry for the state. Hence, 3 million entries are NULL. 

Is there another way to get the states of the applications that would allow me to figure out the count of green patents per state?

Thank you for your help!

Best

Vanessa