For more than a week Linda McMahon’s campaign has been running TV spots accusing U.S. Rep. Chris Murphy of being absent from nearly 80 percent of the hearings for the legislative committees he’s assigned to. But a former Republican congressman said Friday that the ad may be misleading.

McMahon and Murphy are the respective Republican and Democratic nominees for the U.S. Senate seat being vacated by retiring Sen. Joseph Lieberman. But even before both candidates won their primary bids Tuesday night, McMahon was running ads critical of Murphy’s attendance record for the two legislative committees he served on in his first term.

The McMahon campaign launched a new ad Friday, in which the narrator asks “If you skipped 80 percent of the meetings for your job, would you get a promotion?” The ad alleges that Murphy skipped 80 percent of “urgent meetings” aimed at avoiding a meltdown during the 2008 financial crisis.

“Maybe Chris was at the plush, secret congressional health club which you paid for. Or maybe Murphy skipped work to raise money to keep his $170,000 a year job, but Chris Murphy didn’t show up for the job you paid him to do,” the narrator says.

An accompanying press release states that out of a total of 218 hearings by the Government Oversight and Financial Services Committees, Murphy was absent from 170, or 77.9 percent.

But for a number of reasons, former U.S. Rep. Rob Simmons said it may not be accurate to characterize Murphy as skipping work. Simmons lost a Republican primary battle with McMahon in 2010, the first time she ran for U.S. Senate. On Friday he said McMahon’s lack of experience as a lawmaker may be coloring her attacks on her Democratic opponent this year.

“Mrs. McMahon has never served in public office in any capacity. Therefore she has no idea how legislatures—local, state, or federal, how they work,” Simmons said.

McMahon did serve on the state board of education for one year before resigning. She only missed one meeting during that time.

But Simmons said there are a few reasons why lawmakers would not attend hearings. For one thing, they sit on a number of committees and subcommittees, he said. There are times when committees and subcommittees meet at the same time, forcing legislators to either choose one and skip the other or try to split his or her time between the groups, Simmons said.

He said some lawmakers who appear to participate in almost every hearing on paper don’t necessarily spend much time at them.

“Some people I know would go in and register as present then walk out,” he said.

Tim Murtaugh, McMahon’s spokesman, questioned whether Murphy had a scheduling conflict during 80 percent of committee hearings.

Simmons said 20 percent attendance seemed low, but noted there is a difference between informational hearings and committee meetings where lawmakers cast votes on legislation. Responding to an earlier TV spot, the Murphy campaign pointed to Murphy’s high attendance rate for meetings where a vote occurred.

“During his first term, Chris was a very active member of the Financial Services Committee, casting 129 out of 132 votes in the committee and 1,854 out of 1,875 votes on the House floor. Any suggestion otherwise is a lie,” Taylor Lavender, Murphy’s campaign spokeswoman, said in a statement.

Simmons said he felt that being present for a vote was more important than attending hearings, which are designed to give lawmakers an opportunity to learn about issues and ask questions of experts.

“When someone comes to testify, unless it’s really high profile, attendance is not high,” Simmons said.

Part of the reason for that is some lawmakers consider themselves well-versed on certain issues. For instance, Simmons, a retired Army officer, said he considered himself knowledgeable on military issues. He said it helped him when he served on the House Armed Services Committee.

“I didn’t necessarily need to be attending hearings to learn things,” he said.

Simmons said when he was in the House he regularly attended hearings, but he was often multitasking while he was there. He said he would be listening to the hearing with one ear but also focusing on other things like signing letters.

He said some other members attend hearings simply to use them as a soapbox.

“Some members use hearings as a podium, not there to ask questions, there to get on television,” he said.

In particular, the McMahon campaign focuses on two hearings that occurred in October 2008. One was a Government Oversight hearing on the Lehman Brothers bankruptcy. The other was a hearing exploring the role of credit rating agencies in the financial crisis.

“Are you telling me Chris Murphy knew enough about Lehman Brothers?” Murtaugh asked.

Murtaugh said it was up to Murphy to explain why he missed hearings, not Simmons.

“With all due respect to former Congressman Simmons, he doesn’t know why Murphy missed those hearings,” he said.

Murtaugh said for the hearings held by committees tasked with addressing the financial crisis Murphy “was a no show four out of five times. It’s an embarrassment.”

In a press release the McMahon campaign asked if Murphy wasn’t at the two hearings, where was he?

Murphy declined to return phone calls for this report, but his campaign did put out a statement explaining that he was in Connecticut.

“In October of 2008, when the House wasn’t in session, Chris was back in Connecticut talking to his constituents and business leaders about what should be done to save the economy.  When the House was not in session, he thought it was more important to be in Connecticut listening to the people he represented than listening to a panel discussion in Washington,” Lavender said.