Despite the reach of email, asking in person is the significantly more effective approach; you need to ask six people in person to equal the power of a 200-recipient email blast. Still, most people tend to think the email ask will be more effective.

In research Mahdi Roghanizad of Western University and I conducted, recently published in the Journal of Experimental Social Psychology, we have found that people tend to overestimate the power of their persuasiveness via text-based communication, and underestimate the power of their persuasiveness via face-to-face communication.

We found that people were much more likely to agree to complete a survey when they were asked in-person as opposed to over email. These findings are consistent with previous research showing that people are more likely to comply with requests in person than over email.