Table 3.

Percent Change from Baseline to Follow-Up in Number of Brief Interventions Delivered by Treatment Group and Prior Brief Intervention Experience

Prior BI experience	In-person vs. Mail	Web vs. Mail
	% differencea	% differenceb
3 month, follow-up
BIs in the past 90 days	−31%***	−18%***
BIs in the past 30 days	−18%**	−15%**
6 month follow-up
BIs in the past 90 days	−6%***	−30%***
BIs in the past 30 days	+1%	−20%**
No prior BI experience	In-person vs. Mail	Web vs. Mail
	% difference	% difference
3 month, follow-up
BIs in the past 90 days	+6%	+27%***
BIs in the past 30 days	−17%	−22%*
6 month follow-up
BIs in the past 90 days	−8%	−10%
BIs in the past 30 days	−7%	+14%

^*p < .05

^**p < .01

^***p < .001

^aDifference between In-person and Mail, as a percent of Mail (denominator).

^bDifference between Web and Mail, as a percent of Mail (denominator).