J. Lee Annest, Ph.D. Director, Office of Statistics and Programming National Center for Injury...

J. Lee Annest, Ph.D. Director, Office of Statistics and

Programming

National Center for Injury Prevention and Control

TMTM

Using FARS data to Classify Unspecified MV-traffic Deaths by

Person Type in NVSS data

How many MV-traffic deaths are occupants in the vehicle?

The Question

In 2001, almost 35% of 42,443 MV-traffic deaths in the NVSS were unspecified for person type (occupant, motorcyclist, pedal cyclist, pedestrian, other)

Current death certificate used in most states not set up to routinely capture person type

New death certificate has a separate data item that should help classify MV traffic deaths by person type (needs to be assessed)

The Problem

Use data from the Fatal Analysis Reporting System (FARS) to allocate unspecified MV-traffic deaths into specified person type categories (occupant, motorcyclist, pedal cyclist, pedestrian, other)

One Possible Solution

Use the known distribution of FARS deaths for specified person type to determine where to allocate the unspecified MV-traffic deaths in the NVSS.

Method

First, allocate unspecified deaths into specified person type categories other than occupant

Then, put the remaining unspecified MV-traffic deaths into occupant.

Allocation Process

1. Distribute MV-traffic deaths into person type categories within specific age-by-sex groupings

2. Allocate unspecified deaths into person type categories other than occupant as follows:> If the number of specified death is higher in FARS than NVSS, then change NVSS to the higher number> If the number of specified deaths is higher in NVSS than FARS, then do not change NVSS

Allocation Rules Applied

Pedal cyclist (Males 15-19 years)

Deaths

Data Source Observed Allocated

FARS 66 --

NVSS 57 66

----------------------------------------------------

Redistributed unspecified = 9

Example

Pedestrian (Females 1-4 years)

Deaths

Data Source Observed Allocated

FARS 35 --

NVSS 56 56

----------------------------------------------------

Redistributed unspecified = 0

Example

3. Allocate the remaining unspecified deaths to the occupant category

4. Sum deaths across age-by-sex groupings to get final numbers: overall and by broader age and sex groups.

5. After allocation, the distributions of MV-traffic deaths by person type should be very similar for FARS and NVSS

Allocation Rules Applied

Allocation procedure works well for obtaining national estimates

Procedure not tested for state and local estimates; need to consider:

> FARS deaths – reported by where the fatal crash occurred

> NVSS deaths – often reported by place of residence rather than place of occurrence

Conclusions