On the Louisiana Senate floor this month, one lawmaker shared a dirty little secret about a calculation some prosecutors make when deciding what charges to level against a felony suspect.

Sen. Dan Claitor, R-Baton Rouge, served as an assistant district attorney in New Orleans in the late 1980s. He recalled filing more severe felony charges than the evidence might have warranted against some criminal suspects — simply to ensure that jury unanimity would not be required.

“I’m going to put myself out there that, if I had a particularly hard case and I had the opportunity to have a more difficult felony, that I would upcharge ’em,” Claitor said, “because it was easier for me to convict ’em with 10 out of 12 (jurors) — I’m not proud of that — than it is 6 out of 6.”

Prosecutors in Louisiana have broad discretion over such choices. For instance, they can charge a suspect found with a modest quantity of illicit drugs on a possession count — or alternatively, with possession with intent to distribute the drug.

The former would be tried by a “six-pack” jury, where unanimity is required. The latter, because the sentence is necessarily “at hard labor,” demands a jury of 12 — only 10 of whom must agree, even if they ultimately find a defendant guilty only of simple possession.

The same calculation could apply to a robbery case. Defendants charged with simple robbery are tried by a six-member jury, while 12-member juries hear cases of second-degree robbery.

The Advocate’s review of thousands of jury trials over a six-year period — including those involving both types of juries — suggests that the tactic Claitor revealed may in fact improve prosecutors’ chances.

Although it’s tricky to compare across jurisdictions, the data indicate that defendants who go to trial in Louisiana face longer-than-usual odds.

In more than 1,800 trials with 12-member juries from The Advocate's database, 81 percent ended with the jury — or at least 10 jurors — voting to convict a defendant of at least one charge.

That’s well above the 71 percent rate reported by the National Center for State Courts in a 2003 survey of 30 large counties across the country.

The disparity may result in part from the lower bar to conviction that nonunanimous verdicts allow. The Advocate’s review also found that 12-member juries in Louisiana are more likely to convict than six-member juries drawn from the same pools of residents.

In 679 “six-pack” jury trials in The Advocate's database, 70 percent ended with a conviction on at least one count — a rate more in line with the overall national trial conviction rate.

Those six-member juries don’t necessarily mean the punishment can’t be steep if they convict.

Simple robbery, for instance, carries a maximum seven-year sentence in Louisiana. The top sentence for simple burglary is 12 years. Both charges are tried by six-pack juries. And the same habitual-offender law applies, allowing for greatly increased penalties, should prosecutors invoke it following a conviction by either type of jury.

The Advocate’s trial database, for instance, includes 14 defendants who received life prison terms as a result of guilty verdicts by six-member juries.

But along with giving prosecutors two free outs in jury selection, 12-member jury trials often mean a longer menu of lesser charges on which a jury can decide to convict instead of the most severe charge — offering a wider scope for compromise guilty verdicts.

Claitor was arguing this month for a proposal to place a referendum on Louisiana’s 120-year-old split-verdict law before state voters. Just how often prosecutors actually file more severe charges for the reasons he suggested is almost impossible to know.

Other former prosecutors acknowledged that "upcharging" is common practice but gave varied accounts for whether the size of the jury enters into the equation.

Most said the benefit of having one or two jurors whose votes don’t matter — “mulligans,” as Claitor described them — takes a back seat to the greater leverage that more serious charges afford prosecutors in plea negotiations.

Orleans Parish Criminal District Court Judge Keva Landrum-Johnson, who became the city’s first female district attorney in 2007, insisted that jury size didn’t come into play while she was a prosecutor.

“I felt like if a case could be proven, I could prove it either way,” to a six- or 12-person jury, she said.

But Graham Bosworth, a defense attorney who worked in the same DA's Office from 2005 to 2010, mostly in the appeals section, recalled such discussions.

“I’m not surprised that Sen. Claitor admitted he’s done it. It’s definitely part of the conversation,” Bosworth said. “I was involved in a couple of those discussions, be it drugs or crimes of violence.”

Former prosecutors often say their goal was to convince the whole jury; then, if one or two went astray, they still had a conviction.

But Kevin Boshea, a New Orleans-area defense attorney who once prosecuted cases alongside the current Orleans Parish district attorney, Leon Cannizzaro, said they all learned to count.

“I used to pick juries with Leon,” Boshea said as he began to mimic Cannizzaro's brusque cadence.

"He'd say, ’Kevin, are there 10 up there? Do we have 10?' ”

A spokesman said Cannizzaro couldn’t recall the episode.

Follow John Simerman on Twitter, @johnsimerman.