The worst-kept secret on Capitol Hill? Senators miss committee hearings and meetings. All the time.

Unless the senator wields the gavel, he or she may only show up for five minutes, or when it is their turn to ask questions. The results include guffaw-inducing scenes where even senior lawmakers enter the wrong hearing room, misidentify a witness and question the wrong person on the other side of the dais.

But out on the campaign trail, a less-than-stellar attendance record has become the political ammo in a number of Senate races, with criticism of incumbent lawmakers flying in Alaska, Kentucky, North Carolina, New Hampshire, Colorado and Iowa.

This cycle, much of the fodder has come from committee attendance records, at least compared to floor votes. It might look bad back home, but consistent committee attendance defies a reality on Capitol Hill.

“It might make for a compelling campaign ad to whack an incumbent for missing a committee hearing or markup, but the truth is that most legislating gets done outside of the hearing room,” one former Senate committee aide said in an email. “Obviously, it’s impossible for any senator to attend every meeting of the committees to which they belong, which is why staffers exist: to cover the hearing or ensure that the member can vote by proxy.”

After a Tuesday evening debate, Sen. Kay Hagan, D-N.C., conceding she had missed a delayed hearing for a fundraiser. Hagan faces state Speaker Thom Tillis, a Republican, in one of the most competitive races of the cycle.

“There was one, and what had happened at that hearing is that it was scheduled earlier in the day. Votes were scheduled and that hearing had to be postponed to later that day,” Hagan told reporters, according to a video clip of the news conference. “So yes, I did miss that one.”

Hagan’s campaign noted she also turned the attack back on Tillis, pointing to the Charlotte Observer editorial board’s criticism from last year in which they called for him to step aside from the legislature.

Politifact, in responding to an ad against Hagan, went through the public records of the Armed Services open hearings to tabulate attendance, finding a number of senators present less than half the time. The website noted the difficulty getting an accurate read because of the large number of closed meetings.

In the New Hampshire Senate race, former Sen. Scott P. Brown, R-Mass., launched a new round of ads against Sen. Jeanne Shaheen, D-N.H., this week, pointing out in a new ad that she missed a hearing about the Islamic State of Iraq and Syria.

“As a member of the Senate Foreign Relations Committee, she skipped a key hearing, where a top official gave an early warning about a new terrorist group known as ISIS,” says an announcer in the Brown campaign spot.