Colorado DUI HGN expert witness re Horizontal Gaze Nystagmus scientific accuracy

Greg Kane, MD

SFST, DRE & Horizontal Gaze Nystagmus Expert Witness Let me help you
	Exclude junk science HGN and SFST evidence
	Show the jury that the officer's conclusion about your client's impairment would not have happened but for his reliance on a test that is highly inaccurate.

HGN is "scientific" only in the sense that it has been studied by science. What NHTSA's own HGN validation studies prove is, HGN is pretty much a carney trick. In NHTSA's 2007 The Robustness of the HGN Test study:
	NHTSA now admits 6 HGN clues is consistent with a BAC of 0.06% — the data prove it is actually consistent with a BAC of 0.019%. That's not a typo: 0.019%.
	NHTSA now admits 4 HGN clues is consistent with a BAC of 0.03% — the data prove it is actually consistent with a BAC of 0.016%.
	HGN wrongly implicated 85% of innocent people with a BAC less that 0.05%
	When people were tested and immediately retested, a different officer scored their HGN differently 60% of the time.
Does your client's arresting officer know these scientific facts? Does the jury?

Changing the rules in the middle of the game
One way NHTSA makes HGN look accurate is to change the rules in the middle of the game. When it's own 2003 study proved the HGN test officers have been using for years leads to incorrect arrests and false convictions, NHTSA quietly changed the rules. When NHTSA finally reported these results in 2007, it hid the test's inaccuracy by inventing new interpretation criteria, criteria pulled and stretched to make this one data set look good.

The result? NHTSA reported, hey presto, HGN is still accurate.

What the agency didn't do was tell police. What the agency didn't do was tell prosecutors. What the agency didn't do was tell defendants. The agency has not updated the HGN interpretation criteria used in the field and in court.

What the latest science proves is, HGN never did work and it still doesn't.

HGN theory 1998 - 2009

The 1998 criteria

NHTSA admits SFSTs are valid only if these standardized interpretation criteria are followed

Page 12, Validation Of The Standardized Field Sobriety Test Battery At Bacs Below 0.10 Percent Final Report, Stuster AND Burns August 1998, DOT, NHTSA DTNH22-95-C-05192

"IT IS NECESSARY TO EMPHASIZE THIS VALIDATION APPLIES ONLY WHEN:

"THE TESTS ARE ADMINISTERED IN THE PRESCRIBED, STANDARDIZED MANNER

"THE STANDARDIZED CLUES ARE USED TO ASSESS THE SUSPECT'S PERFORMANCE

"THE STANDARDIZED CRITERIA ARE EMPLOYED TO INTERPRET THAT PERFORMANCE.

"IF ANY ONE OF THE STANDARDIZED FIELD SOBRIETY TEST ELEMENTS IS CHANGED, THE VALIDITY IS COMPROMISED."

Page VIII-19, 2006 DWI Detection and SFST Student Manual

When NHTSA validated SFSTs in 1998, it (falsely) claimed officers used the 4 HGN clues means BAC > 0.08 interpretation criteria.

The DOT/ NHTSA SFST Student Manual is clear -- the SFST is valid only if it is done as tested in the study. If the interpretation criteria are changed, the test is not valid.

HGN fact 2003 - 2007
NHTSA research proves the standardized HGN interpretation criteria give false results

NHTSA's new HGN interpretation criteria

Page 15, The Robustness of the Horizontal Gaze Nystagmus Test Final Report September 2007, Burns, DOT, NHTSA DTNH22-98-D-55079

What this extract from NHTSA's latest HGN study doesn't let on is, in this study there were only two subjects with BACs less than 0.03. And they also scored 4 HGN clues!

In 2003 NHTSA tried to validate HGN again. Using the established standardized criteria, the test failed to validate. As many as 92 percent of innocent people failed.

In 2007, when NHTSA finally published the results of this research, it changed the criteria used to assess HGN accuracy.

Now 4 clues means BAC is 0.016 !
0.03...
0.05...
0.06...
0.10...
Or 0.35.

And
6 HGN clues is consistent with BAC 0.06 — or 0.019 !

That's one way NHTSA science proves HGN doesn't work. There are lots of others.

If you're a DUI defense attorney, call me to chat about how I can help you help your clients.

Email: FST (at) FieldSobrietyTest.info
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