Is it possible to set a goal where you’re meant to keep the metric (ie word count etc) in between a certain range?
It is not. This is a somewhat often requested feature but it’s likely it will ever happen.
In the meantime, you should be able to accomplish this by having two goals (a Do More and a Do Less) with an IFTTT/Zapier trigger that mirrors data from one to the second. So you will do your data entry only once but get the desired effect.
Good question, and helpful answer from @drtall (thank you!).
We also have a long-winded and mostly non-helpful answer on the blog:
Maybe you could set a “less than” goal and score your difference from the middle of the range? So you want to write between 500 and 1000 words a day, middle of the range is 750, you would set a goal of “less than 250 words away from 750” . Thus 800 would score 50, while 600 would score 150. Bit fiddly, but it might be useful?