Didn't investigate it at all. Not really sure if it would or wouldn't be meaningful. Just thinking off the top of my head, Word of Mouth should be generated by

Didn't investigate it at all. Not really sure if it would or wouldn't be meaningful. Just thinking off the top of my head, Word of Mouth should be generated by ad spend. It's measuring ad efficacy in a way. Which might be better than ad spend (total dollars) for predicting success.