Meaning of missing values in eyewitness recall and accident records.
BACKGROUND
Eyewitness recalls and accident records frequently do not mention the conditions and behaviors of interest to researchers and lead to missing values and to uncertainty about the prevalence of these conditions and behaviors surrounding accidents. Missing values may occur because eyewitnesses report the presence but not the absence of obvious clues/accident features. We examined this possibility.


RESULTS
Participants watched car accident videos and were asked to recall as much information as they could remember about each accident. The results showed that eyewitnesses were far more likely to report the presence of present obvious clues than the absence of absent obvious clues even though they were aware of their absence.


CONCLUSIONS
One of the principal mechanisms causing missing values may be eyewitnesses' tendency to not report the absence of obvious features. We discuss the implications of our findings for both retrospective and prospective analyses of accident records, and illustrate the consequences of adopting inappropriate assumptions about the meaning of missing values using the Avaluator Avalanche Accident Prevention Card.
Uttl
Bob
B
Mount Royal University, Calgary, Canada. uttlbob@gmail.com
Kisinger
Kelly
K
D000063:Accidents, Traffic / Q000331:legislation & jurisprudence* / Q000517:prevention & control; D001336:Automobiles / Q000331:legislation & jurisprudence*; D006801:Humans; D011939:Mental Recall; D011996:Records
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