Here’s the AP‘s summary of yesterday’s BP oil spill flow rate developments.

With each new look by scientists, the oil spill just keeps looking worse.

New figures for the blown-out well at the bottom of the Gulf of Mexico show the amount of oil spewing may have been up to twice as much as previously thought, according to scientists consulting with the federal government.

That’s very far from being true. (The piece was written by Seth Borenstein and Harry R. Weber). The key to understanding why is to ask: up to twice as much as previously thought by whom?

What happened yesterday was that the government’s expert panel, the Flow Rate Technical Group, updated their own prior estimate.

Their prior estimate was 12,000 to 19,000 barrels a day. That is to say, that’s what they decided to push, even though their own high-end estimate was 25,000 barrels a day:

The team’s best estimate for the amount of oil pouring from the well is 12,000-19,000 barrels per day, though one of three measurement methods the team used returned a high-end rate of 25,000 barrels per day, McNutt said.

That’s U.S. Geological Survey Director Marcia McNutt, saying: “Even though we have to put ‘up to 25,000 barrels per day’ in our report — because someone on the team came up with it, and would not be browbeaten into retraction or reduction — please discount that, and just embrace 12,000 to 19,000 as the range.”

Their new estimate suffers from similar consensus issues:

Three different groups of scientists making educated guesses have come up with upper and lower ranges that go as low as 12,600 barrels a day and as high as 50,000 barrels a day. Marcia McNutt, the federal official charged with determining the flow rate, cited the range of about 20,000 to 40,000 barrels a day as the official estimate.
[...]
All those numbers come with the caveat that they estimate the flow from the well before a kinked riser pipe was lopped off on June 3, a move that inevitably increased the flow, although to what extent remains unclear.
[...]
These estimates still carry with them a great deal of uncertainty. One group estimated a range from 12,600 to 21,500 barrels a day; another estimated a range from 25,000 to 50,000 barrels a day.

(Did you notice how one team using three measurement methods has suddenly morphed into three different groups of scientists? And somehow one group’s estimates seem to have slipped through the cracks entirely, ha ha!)

What we have here, then, is that the Flow Rate Technical Group’s official estimate has been increased from 12,000–19,000 to 20,000–40,000.

So when the AP goes “the amount of oil spewing may have been up to twice as much as previously thought”, what it means is “as previously thought by the Flow Rate Technical Group”. Which makes this a really good time to remember that their previous thinking was based on what was undoubtedly a very careful analysis of just seven minutes of low-quality video carefully selected for them by BP.

And the fact of the matter is that with yesterday’s revision, the Flow Rate Technical Group has still not quite caught up with what scientists who actually conducted a rigorous analysis untainted by the long arm of BP were saying four weeks ago:

Steven Wereley, an associate professor of mechanical engineering at Purdue University, analyzed videotape of the seafloor gusher using a technique called particle image velocimetry.

A computer program simply tracks particles and calculates how fast they are moving. Wereley put the BP video of the gusher into his computer. He made a few simple calculations and came up with an astonishing value for the rate of the oil spill: 70,000 barrels a day — much higher than the official estimate of 5,000 barrels a day.

The method is accurate to a degree of plus or minus 20 percent.

Given that uncertainty, the amount of material spewing from the pipe could range from 56,000 barrels to 84,000 barrels a day.
[...]
Timothy Crone, an associate research scientist at the Lamont-Doherty Earth Observatory, used another well-accepted method to calculate fluid flows. Crone arrived at a similar figure, but he said he’d like better video from BP before drawing a firm conclusion.

So when the AP tells us “With each new look by scientists, the oil spill just keeps looking worse”, that really doesn’t seem to uniquely comport with the truth.

 
Previous posts:
June 9: BP Spill Rate: Some New (And Improved) Developments
June 7: The Spill Rate Estimate That Walks On Water Has Feet Of Clay
June 7: How Much Oil Would The Oil Spill Gush (If BP Could Gush Truth)?
June 1: The Long Arm Of The Stock Market
May 27: Quote Of The Day
May 26: Scenes From A Spill
May 24: How Retarded Can One Corporation Be?
May 18: BP’s Strategy Pays Off
May 17: On The Evolution Of The Deepwater Horizon Spill Rate Estimate