What is CODES? Maine CODES Linked Data Publications Other Highway Safety/Injury Links

Maine CODES Linked Data

How is data linked?

Maine and each of the other CODES states use the same software, CODES2000, to link police crash and medical records. In the absence of any unique identifier to link occupants of vehicles to medical records, probabilistic linkage methods are utilized. Using crash date, crash location, age and gender of occupant, birth date of driver from the police crash files, with date and location of EMS response, hospital destination, hospital of admission, date of birth in the medical files, records can be linked with reasonable accuracy.

Further information about CODES linkage software can be found at the NHTSA CODES Forum web site.

What is imputation?

Currently, the Maine CODES project uses "high probability" linked records.

Due to the quality of the data used for linkage not all records can be linked. For example, a police crash report missing occupant date of birth is less likely to be linked than a record that contains a date of birth. Resulting CODES files underestimate the complete burden of injury and cost. Recognizing this issue, in order to develop better statistical estimates, NHTSA has promoted use of imputation methods in CODES. Imputation has also been used by NHTSA for reporting of blood alcohol levels.

The CODES2000 software and linkage process has been modified to develop imputed linkages resulting in higher proportion of records linked.

Maine CODES Data Sources The Maine CODES project currently links police crash records to EMS, hospital inpatient, hospital emergency department, and death certificate records.

The police crash report data is provided by the Maine Department of Transportation. The EMS by Maine Emergency Medical Services, the hospital inpatient and emergency department by Maine Health Data Organization, and death certificate records by Maine Office of Data, Research, and Vital Statistics.

Maine CODES Linkage Process Manual - currently under development

Maine CODES Data Dictionary - currently under development

Maine CODES Current Linked Data Files Maine CODES linked data currently consists of "high probability" links. Among 761,513, occupants involved in motor vehicle crashes between 1995 and 2002, 101,172 were linked to EMS, 16,191 to emergency department visit (2001-2002 only), 7,721 linked to inpatient, 1,291 linked to a death certificate. Linkage rates are provided below.

 

LINKED TO EMS

 

LINKED TO ED

 

LINKED TO IP

 

LINKED TO DEATH

 

YEAR

OCCUPANTS

Count

%

count

%

Count

%

Count

%

1995

97,414

11,161

11.5%

na

  

1,191

1.22%

168

0.17%

1996

99,712

11,414

11.5%

na

  

1,053

1.06%

151

0.15%

1997

103,532

12,525

12.1%

na

  

1,023

0.99%

172

0.17%

1998

99,618

12,287

12.3%

na

  

919

0.92%

157

0.16%

1999

95,003

13,283

14.0%

na

  

942

0.99%

150

0.16%

2000

89,578

13,377

14.9%

na

  

949

1.06%

143

0.16%

2001

90,281

13,455

14.9%

8,232

9.1%

868

0.96%

170

0.19%

2002

86,375

13,670

15.8%

7,959

9.2%

776

0.90%

180

0.21%

2003

                  

TOTAL

761,513

101,172

13.29%

16,191

na

7,721

1.01%

1,291

0.17%

Accessing Maine CODES Data

The process for external organizations to access Maine CODES information is under development. A draft document showing the process and rules governing external access to Maine CODES linked data has been developed. Link to powerpoint showing access process and form

Other Related Data and Technical Resources

For reporting supplemental information on licensed drivers, registered vehicles, vehicle miles traveled, road characteristics, injury types are important. Use the following links.