Partisan phone calls and mail, administered in different combinations. Neither the phone calls nor the mail used independently or together resulted in significant treatment effects.

Partisan phone calls and door-to-door canvassing carried out by a grassroots political network do not result in significant mobilization effects. Higher contact rates could improve estimates.

The quality and timing of GOTV phone calls are more important than message content or whether the calls are made by volunteers or paid professionals. Professional phone banks are found to be cost-competitive with canvassing and leafleting and more effective than the calls placed by volunteers.

Comparing the effects of GOTV calls made by professional phone banks at different stages of a mobilization campaign, results suggest that calls made the week of the election are no more effective than calls made four weeks prior to the election.

Nonpartisan commercial phone bank messages may be more effective than partisan messages. Results may differ across parties and electoral contexts.

Personally delivered phone calls and door-to-door canvassing messages are effective in mobilizing turnout. Phone calls may be as effective as canvassing.

Results from four separate experiments in which varying degrees of partisan or non-partisan messages are presented. Only results from the nonpartisan phone campaign experiment yielded substantive and statistically significant estimated mobilization effects.

Estimates of the effects of door-to-door canvassing and phone call campaign experiments are compromised by low contact rates and treatment of control group subjects.