After the 20,000 “direct jobs,” the second most popular tally cited by the media has been 118,000 “spin-off jobs,” and it, too, has a long, convoluted history. It comes from a June 2010 report from The Perryman Group, a financial analysis firm based in Texas that was hired by TransCanada to evaluate Keystone XL. That report estimated, in a very non-transparent way, that the pipeline would create 118,935 person-years of employment over the hundred-year life of the project.

TransCanada first cited the figure in a September 2010 press release (which failed to mention the century-long time frame). But two months later, it issued another press release that dispensed with person-years and mistakenly referred to “118,000 spin-off jobs” instead. The error was repeated in dozens of media reports.

The Perryman Group did, in fact, estimate the “spin-off” jobs that result from “the permanent increase in stable oil supplies associated with the implementation of the Keystone XL Pipeline”: 250,348 under a “normal oil price scenario” and 553,235 under a “high oil price scenario.” And these figures formed the basis for countless media assertions that the pipeline would create hundreds of thousands of jobs, but they are highly suspect. A report to Congress submitted by the State Department took issue with the numbers, stating:

The economic analysis conducted for the EIS under contract to the Department of Energy, however, indicates that Keystone XL is unlikely to have any impact on the amount of crude oil imported into, or refined in, the United States. Therefore, it would not be reasonable to suggest the pipeline would cause an increase in employment or other economic activity by increasing crude oil imported into the United States.

“Regarding employment, the construction of the Keystone XL pipeline would likely create several thousand temporary jobs associated with construction; however, the project would not have a significant impact on long-term employment in the United States,” the State Department concluded.

That’s the bottom-line best guess for reporters: a few thousand temporary construction jobs over the course of a couple of years. Permanent jobs operating and maintaining the pipeline once it’s built probably wouldn’t add up to more than a few hundred. Everything else is unsubstantiated spin.

But estimates in the press have ranged wildly. A Media Matters video released last week—amusingly titled “To Infinity and Beyond”—presented a montage of various reports from conservative media over the last few months, led by Fox News, which placed job-creation everywhere from thousands, to tens of thousands, to hundreds of thousands, to a million. The dissonance is maddening.

The print media haven’t been quite as bad. In recent months, outlets like The New York Times, The Washington Post, USA Today, Politico, and the Pittsburgh Post-Gazette have done a good job challenging industry estimates. NPR, too, has been good on this. But others, including The Wall Street Journal, The Christian Science Monitor, and many smaller papers have uncritically repeated the 20,000 jobs figure since Obama rejected Keystone XL, despite plenty of evidence that it is misleading.

With arguments over the pipeline—and energy in general—expected to play a significant role in the presidential election going forward, reporters need to get their numbers straight so that Americans can start having a more informed debate about environmental regulations and jobs.

Curtis Brainard is the editor of The Observatory, CJR's online critique of science and environment reporting. Follow him on Twitter @cbrainard.