Running against President Obama’s jobs record in the Nevada Republican primary, Mitt Romney was stymied by Friday’s announcement that unemployment had declined to 8.3 percent. “Unfortunately, these numbers cannot hide the fact that President Obama’s policies have prevented a true economic recovery,” said a statement issued by his campaign.

But according to a new study, Romney should change his rhetoric — voters don’t care about jobs numbers. Instead, they respond to fluctuations in the Dow Jones industrial average.

The relationship between how an incumbent performs and the changes in inflation, gross domestic product and unemployment is “often insignificant,” according to Robert R. Prechter Jr., Deepak Goel, Wayne D. Parker and Matthew Lampert’s “Social Mood, Stock Market Performance and U.S. Presidential Elections,” a study produced by Atlanta’s Socionomics Institute. “Voters unconsciously credit or blame the leader for their mood” — and the best indicator of mood isn’t joblessness, they say; it’s the Dow.

This may be bad news for Romney and the other Republican contenders — despite the European debt crisis and a decline in housing prices, the Dow has hit its highest point since 2008. The Socionomics study contends that citizens vote “in accordance with trends in social mood” and that “stock market indexes appear to be the best available indicator of social mood, because investors can act swiftly in this context to express their optimism and pessimism.” If recent market trends hold steady, the country could be in too good a mood to oust the president.

“A newcomer’s chance of success improves when competing against an incumbent who has served during a period of declining social mood,” the study states.

Meanwhile, if the market tanks, the authors say, Obama may want to consider forgoing his nomination, LBJ-style: “An incumbent who has held office during a major setback in social mood may wish to consider declining to run for a second term and await more favorable conditions to pursue the presidency again or retire from presidential politics to spend hard-earned political capital on other efforts.”