David,
I agree that phone or face to face is best, however I find it very difficult to contact students by any means when they are off campus. Most students are texting or posting on social media sites and rarely even check e-mail any more. I emphasize the importance of staying in contact with instructors and students give all of their contact information (cell phone, e-mail, home phone). I spend so much time trying to contact students when they are off campus I pull my hair out! And when they return and I ask why they didn't return my call, the common answer is "I didn't get a call".
