Constituents who participate in online town halls are more likely to vote for their Member of Congress and approve of his position on the issue discussed than those who don't participate, according to a study released Monday .

The findings open up a new possibility in the wake of August's heated town halls on health care reform, where dozens of Members faced angry crowds and where policy questions often become overshadowed by loud accusations.

Conducted by the Congressional Management Foundation, the study found that online town halls led to "high quality" discussions that were "extremely popular" with constituents.

"People universally loved this and felt very positively about it," said Kathy Goldschmidt, CMF's deputy director. But she added, "We don't in any way recommend that these are replacements for [in-person] town halls."

Most Members interact with constituents in person or through telephone town halls, where thousands of constituents can participate and submit questions with the push of a button.

The online town halls differ slightly: Instead of asking questions by phone, constituents type them into a prompt box and they are immediately put into the queue. Members' responses are provided in audio and in a running transcript on the screen. Members can also use PowerPoint presentations to illustrate their points.

In the CMF study, all but one of the town halls had a group of 15 to 20 constituents — far less than the average "tele-town hall." But researchers say the groups were diverse, representing a wider swath of society than a typical town hall meeting.

Before the town halls, 20 percent of the selected constituents approved of their Member's position on immigration (the issue discussed in 20 of the 21 town halls); after participating, that number jumped to 58 percent. Moreover, 69 percent of participants voted for their Member, compared with 64 percent of control subjects (constituents who participated in the study but not in the town halls).

Swing voters were affected the most. Constituents who only had a 50 percent probability of voting for their Member jumped to 73 percent after participating in the online town hall.

But whether tele-town halls might produce the same effects is unclear. The study focused exclusively on online town halls, and the bulk of it was conducted in 2006 — before most Members had even heard of tele-town halls.