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Keith Vodden Dr. Douglas Smith - Transports Canada

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Analysis and Estimation of the Social Cost of Motor Vehicle Collisions in Ontario<br />

information available through MOH&LTC. It also identifies factors derived from the<br />

ORSAR and revised (MOH&LTC) numbers that are used by the model to adjust<br />

ORSAR-derived numbers for major and minor injuries for 2004 and subsequent years.<br />

Exhibit III-2 Revised Data and Adjustment Factors for Injuries in 2004<br />

MOH&LTC Chipman-* Factors**<br />

based for 2004<br />

Estimate and later<br />

2004 2004 years<br />

(#) (#)<br />

5,293 1.48<br />

60,726 2.03<br />

58,822 1.49<br />

* See discussion on the calculation of minimal injuries in the following text.<br />

** Factors for major and minor injuries are derived from MOH&LTC data, and for minimal injuries from a re-analysis of the Chipman<br />

analysis of the Ontario Health Survey.<br />

d) Additional minimal injuries<br />

The number of minimal injuries cannot be verified or adjusted using MOH&LTC<br />

data, as these injuries do not involve a hospital stay or an emergency room visit. Instead<br />

we use an analysis by Mary Chipman 1 of the 1990 Ontario Health Survey. No more<br />

recent study exists to help estimate the number of minimal injuries. However, given the<br />

age of the study one of the adjustments we make is to reflect the changed mix of injuries<br />

from motor vehicle collision in 2004 compared to 1990.<br />

We make a number of adjustments in the Chipman analysis to fit the needs of the<br />

social cost model. In brief these adjustments:<br />

• Adjust the proportion of injuries to pedestrians and cyclist to reflect the mix in<br />

motor vehicle collisions. The 1990 Ontario Health Survey used a broader<br />

definition of traffic collision that did not need to involve a motor vehicle.<br />

• Reduce the number of emergency room visits by 10% to estimate minor injuries.<br />

This reflects the proportion that becomes major injuries (hospital stays). Using<br />

estimates from the 1990 Ontario Health Survey of emergency room and hospital<br />

room use without adjustment would lead to double-counting otherwise.<br />

• Calculate minimal injuries as a residual by subtracting major and minor injuries<br />

from total injuries.<br />

• Adjust for the changing mix of injury severities between 1990 and 2004 motor<br />

vehicle collisions.<br />

1 Chipman, Mary L., "Health Service Use Attributable to Injury in Traffic Crashes: Data from a Population<br />

Survey," 36th Annual Proceedings, Association for the Advancement of Automotive Medicine, October<br />

5-7, 1992, Portland, Oregon.<br />

18 TNS Canadian Facts, Social and Policy Research

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