Hello - I know 'shorter is better' when it comes to surveys, but was curious if anyone has any data around; survey duration, completion percentage, and invite method. What me and my team have been wrestling with is - what are the acceptable/ideal survey length for a digital site intercept vs. an e-mail survey post visit. 
Does anyone have any data/experience they can share about this? Bonus points if you have completion rates by invite method as well.
Thanks in advance and looking forward to the discussion, and hoping I don't get hit with a bunch of sales pitches.
Allen