The US economy is almost certainly headed back into a double dip recession, and economists aren't seeing it because they're using "the old rules of thumb" that don't apply this time, well-known economist David Rosenberg told CNBC.
Consumers' focus on shedding debt rather than spending will prevent the economy from growing and bring a halt to the recovery, said Rosenberg, a former Merrill Lynch economist who now works at Gluskin Sheff, an advisory firm based in Toronto.
"The risks of a double-dip recession—if we ever got out of the first one—are actually a lot higher than people are talking about right now," he said. "I think that it's almost a foregone conclusion, a virtual certainty."
Rosenberg has long been pessimistic on the economy, believing that persistently high unemployment, weak economic indicators and massive debt-cutting—deleveraging—by consumers and businesses will send the economy into a double dip.
Though many economists disagree with Rosenberg about the chance of another recession, his views are widely followed on Wall Street and have often been accurate.
Unemployment remains stubbornly high at 9.6 percent, while Friday's economic reports showed modest gains in retail spending and the consumer price index.
In addition, a slew of leading economists, from firms including Deutsche Bank, JPMorgan Chase and Goldman Sachs have been scaling back their outlook for the gross domestic product.
On Friday, Goldman raised the chance of a double-dip happening to 25-30 percent. BMO Capital Markets, in its second-half outlook released last week, said consumer weakness has been a hallmark of weak recent recoveries, but this cycle is the worst.
Rosenberg, meanwhile, thinks other economists are relying too much on patterns from past recessions.
"Most economists, most strategists are still deploying the old rules of thumb that worked so well post-1945 where recessions were really just corrections in GDP in what was a secular expansion of credit," Rosenberg said. "People haven't wrapped around their heads what is a credit contraction all about."
While the notion that economic growth will be weak is gaining acceptance, a double-dip, where the economy enters a second phase of negative growth within a year of rebounding, remains a minority opinion.
"Where I disagree is, is the magnitude big enough to take us from a sustained expansion at a very low growth rate into a double-dip recession?" said Richard Hoey, chief economist at BNY Mellon, who appeared with Rosenberg on CNBC. "Among the reasons I don't think we have a double-dip recession is we reliquefied practically every corporation in America...The large corporations have been able to have a huge gain in profits and they're not spending it. So their cash is building up every single day."
The history of previous recoveries shows that double-dips are rare and unlikely except in extreme cases, said Sean Clark, of Clark Capital Management, another guest on CNBC.
"This 12-month recovery, since it bottomed in June of last year, has been stronger than the previous two post-recession periods," Clark said. "Double-dip recessions are very much the exception to the norm."
But Rosenberg said that line of thinking ignores how this downturn, spurred by a credit relapse and fed by a reluctance of businesses and consumers to spend money, is different than others. He pointed out that the household employment survey has declined three months in a row, a condition that indicates a recession 98 percent of the time.
"Comparing to the recessions of the post-World War II period is a total waste of time," he said. "This is a totally different animal."