Congressional candidates don’t get out as much as they used to.

Blame it on the increased pressure to raise more money or video trackers or the way the Internet has transformed voter outreach. Or all three.

There’s no question the flood of spending by outside groups and the overall level of money being spent on elections up and down the ballot has led to a decrease in retail politicking for Members of Congress and House and Senate hopefuls. More and more candidates are ditching the campaign trail to spend more time dialing for dollars.

“Today, because of the staggering amount of money that federal candidates have to raise, the amount of retail campaigning they could do is markedly less than it was four or six years ago,” said David Heller, a Democratic media consultant for two decades.

There is no numeric evidence revealing the drop-off in retail political events, but campaign operatives on both sides of the aisle have noticed the obvious trend.

There are several reasons beyond fundraising that Congressional candidates eschewed the person-to-person contact this cycle. While the pressure to fundraise increased, tightly controlled campaigns avoid putting their candidates in the path of video trackers — or anyone with a cellphone camera — until they must.

The result? More voters meet their Members of Congress through the lens of a negative television advertisement. It’s an ominous circumstance for a Congress with already record-low approval ratings.

In the competitive race for Pennsylvania’s 12th district, aides said the campaigns announced one to two events a day this week. In the mid-October days leading up to Senate debates in Indiana and Ohio, campaigns ceased announced public campaigning for two to three days to prepare.

“Media advisories are a thing of the past,” said Chris LaCivita, a GOP consultant based in Virginia. “There has been a decline, if you will, in the number of retail political events, mostly because the methods of reaching out to voters, specifically through the Internet, have changed the dynamics of campaigning so much.”

Traditionally, the waning weeks before Election Day marked the time when candidates stopped fundraising and focused on get-out-the-vote activities while spending the millions of dollars that they raised on airing TV ads. And October recess kicked off marathon days of glad-handing, baby-kissing and flesh-pressing.

Especially in major media markets such as Cleveland, Chicago and Los Angeles, campaigns now find retail politicking is not worth candidates’ time.

“The bang for your buck is not great if you’re the candidate,” said Rep. Susan Davis (D-Calif.) in mid-October while knocking on doors with San Diego Port Commissioner Scott Peters in Coronado. On that beautiful Saturday afternoon, it was her fourth door without an answer.

The pressure to fundraise is mostly to blame. The advent of outside groups with unlimited cash put candidates’ call time at a premium — at least until there’s no more airtime left to buy.

One House aide running a targeted race described a strict regime of three events a day this week — and only during mealtimes. Every other moment, this House candidate fundraises or, sometimes, calls undecided voters.

“In the last couple of weeks, frankly, I need him on the phones raising money so that we can hope to compete on air and reach more voters,” said another Democratic operative running a top House race.

The receipts tell the larger story: House and Senate races are more expensive endeavors than they were two or four years ago. The top House fundraisers in competitive races bring in, on average, about $1 million more than in 2008.

A study released Wednesday estimated that $6 billion will be spent on the 2012 elections.

“It used to be if a candidate did five or six hours of call time a day, four or even five days a week, that was considered extraordinarily good,” Heller said. “Today, that’s a rock-bottom minimum. And for the most contested races, it’s not nearly enough.”

Of course, much of this depends on the candidate, the campaign and the state.

If the candidate is a self-funder, he can hit the campaign trail as much as possible — such as former WWE CEO Linda McMahon in Connecticut. The Republican nominee for Senate donated $40 million to her own campaign. This cycle, she could afford to attend 240 small events for women and marched in every fair or parade in the state.

In North Dakota, retail politicking is still worth the effort because of the state’s small voting population. This week, Rep. Rick Berg (R) kicked off a statewide tour in his dark green Ford pickup truck, and an aide said he’ll average five stops per day for his Senate bid’s last big push. His opponent, former state Attorney General Heidi Heitkamp, starts a five-day, 30-stop bus tour today in her colorful campaign bus emblazoned with “Bring it home, Heidi,” per an aide.

But those kinds of events are becoming the exception instead of the rule, especially in early to mid-October. It’s rare for reporters to show up to such events in states with dwindling news outlets.

In the final days of a campaign, it’s often more productive for bleary-eyed candidates to turn out the party faithful instead, according to Scott Cottington, a Republican consultant for three decades.

“I just think there’s a general aversion to campaigning on the ground anyway, and I think that’s somewhat a reflection of both sides catering to their base now,” Cottington said. “If I know I can be calling known donors and raising money, most candidates would rather spend their time doing that than going out and meeting people in the crapshoot that’s going out, door to door.”

Of course, for some candidates, it’s advantageous to spend more time behind closed doors. Some Congressional hopefuls aren’t good at chatting up crowds, while others have a gaffe habit. In the YouTube age, it’s easier to leave the personal appeal for the straight-to-camera spot.

“We owe it to our clients to make sure they don’t get ambushed,” LaCivita said. “That’s just responding to the times. No one wants to see their client bushwhacked by some half-cocked blogger.”

Kyle Trygstad contributed to this report.