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The experience gained from processing MDAI cases and the inconsistencies in ACAS coding. It describes the process of developing a common and consistent set of ACAS coding and the importance of maintaining consistency and accuracy. The document also mentions the implementation of a trauma thesaurus and the need for further research.
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MULTIDISCIPLINARY ACCIDENT INVESTIGATION DATA FILE
1974 Final Report
4. T i t l e a n d S u b t i t l e ~ultidisciplinaryAccident Investigation Data March^1975 File, 1974 Final Report 6. P e r f o r m i n g O r g a n i z a t i o n C o d e
T E C H N I C A L R E P O R T S T A N D A R D T I T L E P A G E 3
1. R e p o r t N o. 3.^ R e c i p i e n t ' s^ C a t a l o g N O.
1 6. A b s t r a c t
2. Government A c c e s s ~ o nN O.
9. P e r f o r m i n g^ O r g o n t z o t ~ o nN o m e^ and^ A d d r e s s Highway Safety Research Institute Huron Parkway and Baxter Road Ann Arbor, Michigan 48105 '
National Highway Traffic Safety Administration Department of Transportation Washington, D.C. 20590
This is the final report of the 1974 Multidisciplinary Accident Investigation (MDAI) Data File contract. It contains a summary of contract accomplishments and a discussion of data preparation, data files and the data system. Appendices include a list of all contract documentation and an index of all automated MDAI report DOT-HS pub- lication numbers.
1974 through March 31,
1 4. Sponsoring A g e n c y C o d e
About 10,000 clinical accident investigations have been conducted to-date (March 1975). These reports sponsored by the National Highway Traffic Safety Administration, the Motor Vehicle Manufacturers Association, and the Canadian Department of Transporta- tion, are being edited and processed into a common data base. All sFonsors are also being provided direct access to the data base , through the University of Michigan's time-shared computer system via i remote batch and interactive terminals. The data base contains data recorded on an annotated "Collision Performance and Injurv Report."
Automation of Accident Reports;
I
Unlimited
Base,
F o r m DOT F 1700.7 ( 8 - 6 9 )
19. S e c u r i t y C l a s s i f. ( o f t h i s report) 20.^ S e c u r i t y^ C l a s s i f.^ ( o f t h i s^ page) 21.^ No.^ of^ P a g e s^ 22.^ P r i c e
- 1.1 Background - 1.2 Work Accomplished. CPIR Case Vehicles in Computer Files. April. 1974 .March. 1975 ............................. 10
CPIR Case Vehicles Edited. April. 1974 - March. 1975 ............................. 10
Sources of Data and Remote Terminal Users ............. 40
Case Processing Status. April 1. 1974 - March 31. 1975 ......................... 3
File Usage Statistics. May. 1974 through November. 1974 ....................... 5
Processed MDAI Case Vehicles. by Team .................. 9
MDAI Cases Selected for Trial Coding .................. 17
Average Number ACAS Factors Coded per Case and per Coder ................................^19
Four-Digit ACAS Factor Coding Consistency ............. 20
Two-Digit ACAS Factor Coding Consistency .............. 21
Summary of Files Presently Available in the Data System .................................... 41
Data ~anipulationFunctions Available in the ADAAS System ................................... 43
T h i s was accomplished d u r i n g t h e f i r s t s i x months of t h e con- t r a c t. The remainder of t h i s s e c t i o n d i s c u s s e s t h e work accomplished under each of f i v e t a s k s. The n e x t t h r e e s e c t i o n s d i s c u s s , i n t u r n , d a t a p r e p a r a t i o n and q u a l i t y c o n t r o l , MDAI d a t a f i l e s , and t h e d a t a system. The f i n a l s e c t i o n c o n t a i n s t h e c o n c l u s i o n s and recommendations.
The 1974 c o n t r a c t provided f o r f i v e s p e c i f i c t a s k s : Task S h o r t T i t l e 1 Case P r o c e s s i n g 2 New V a r i a b l e s 3 E d i t i n g Documentation 4 d rain in^ 5 P r e p a r a t i o n of S p e c i a l F i l e s
Task 1: Case P r o c e s s i n g The f i r s t t a s k c o n s i s t e d of p r o c e s s i n g MDAI c a s e s i n t o computer s t o r a g e. From A p r i l , 1974, through March, 1975 ( t h e l a t e s t computer f i l e u p d a t e ) , 1 , 9 9 3 MDAI c a s e v e h i c l e s were added t o t h e computer f i l e ( i n c l u d i n g 1973-1974 Calspan c a s e s p r o c e s s e d under Motor V e h i c l e M a n u f a c t u r e r s A s s o c i a t i o n spon- s o r s h i p ). A t o t a l of 7,799 c a s e v e h i c l e s from a l l s p o n s o r s a r e c u r r e n t l y (March 1975) i n computer s t o r a g e and a v a i l a b l e t o NHTSA ( s e e T a b l e 1). T r a f f i c U n i t Compendium ( T U C ) forms f o r 5,409 t r a f f i c u n i t s ( e. g. , c a r s , p e d e s t r i a n s ) were a l s o coded and p r o c e s s e d a s a n a d j u n c t c a s e i n v e n t o r y o p e r a t i o n. I n j u r y^ s e v e r i t y r e c o d i n g u s i n g t h e new AIS-6 d e f i n i t i o n (1) was performed f o r 341 c a s e s ,
Case P r o c e s s i n g S t a t u s A p r i l 1, 1974 - March 31, 1975
I n C o n t r a c t N e w Case P r o c e s s i n g P e r i o d T o t a l
1 4 1 ( a c c i d e n t s ) 333 192
Pre-Crash New V a r i a b l e s Coded: 170 ( v e h i c l e s ) 170
VCMR1s p r o c e s s e d : 943 ( v e h i c l e s ) 1,
AIS-6 recoded: 341 ( v e h i c l e s ) 341
Q u a l i t y c o n t r o l was ensured by a d e q u a t e t r a i n i n g of d a t a e d i t o r s , complete key v e r i f i c a t i o n of keypunched d a t a , and computer checking of d a t a i n c o n s i s t e n c i e s. Feedback t o f i e l d MDAI teams was provided by i n d i v i d u a l c a s e c r i t i q u e s t b y pre- s e n t a t i o n s on November 1 4 , 1974, t o t h e M D A I t r a i n i n g c o u r s e conducted a t t h e U n i v e r s i t y of Southern C a l i f o r n i a (USC), and by documentation of t h e e d i t i n g p r o c e s s and r e f e r e n c e informa- t i o n. Update s h e e t s t o t h e 1973 e d i t i o n of t h e e d i t i n g manual ( 2 ) were provided i n J u l y , 1974, and t h e e n t i r e manual was updated and r e i s s u e d i n March, 1975 ( 3 , 4 ). Task 2 - New V a r i a b l e s S e v e r a l new v a r i a b l e s , developed under t h e p r e v i o u s MDAI r e p o r t p r o c e s s i n g c o n t r a c t (DOT-HS-031-3-589) (5), were coded f o r 170 MDAI c a s e s under Task 2 of t h i s c o n t r a c t. The new v a r i a b l e s i n c l u d e approximately 2 0 0 C P I R supplementary ques- t i o n s - - p r i m a r i l y concerned w i t h p r e c r a s h a s p e c t s. (^) Based on t h e 1974 t r i a l coding e x p e r i e n c e , a p r o t o t y p e MDAI p r e c r a s h
F i l e Usage S t a t i s t i c s May 1974 through November 1974 NHTSA T o t a l NHTSA % % of a l l F i l e Group Accesses Accesses of T o t a l * NHTSA Uses** BMCS CPIR DENVER EXPOSURE FLORIDA M I C H I G A N NEW YORK TEXAS TURNPIKE WASHINGTON
*NHTSA usage of t h e s p e c i f i e d f i l e a s a p e r c e n t a g e of a l l usages of t h a t f i l e ; e. g. , 57.8 p e r c e n t of a l l Texas f i l e
**NHTSA usage of t h e s p e c i f i e d f i l e a s a percentage of a l l NHTSA f i l e usages d u r i n g t h e p e r i o d i n d i c a t e d.
Task 5 - P r e p a r a t i o n of S p e c i a l F i l e s A new MDAI F a t a l F a c t o r s F i l e (FFF) c o n t a i n i n g 333 MDAI f a t a l c a s e s was c o n s t r u c t e d. The f i r s t codebook and f i l e a c c e s s was provided December 27, 1974. It o r i g i n a l l y contained 1 4 1 c a s e s coded by NHTSA. Subsequently HSRI coded an a d d i t i o n a l 1 9 2 c a s e s and provided an updated codebook and f i l e a c c e s s on A p r i l 1 4 , 1975.
merged. T h i s merger i n d i c a t e s , among o t h e r t h i n g s , which c a s e v e h i c l e s i n t h e TUC f i l e have n o t y e t shown up i n t h e CPIR f i l e. The a c t u a l e d i t i n g of e a c h c a s e i s performed i n d i v i d u a l l y by t h r e e s p e c i a l i s t s. The f i r s t e d i t o r checks each c a s e f o r c o n s i s t e n c y w i t h i n t h e c o d i n g forms and w i t h t h e n a r r a t i v e ,
Each c a s e i s t h e n e d i t e d by v e h i c l e damage and occupant i n j u r y s p e c i a l i s t s. The v e h i c l e damage e d i t o r checks t h e v e h i c l e damage q u e s t i o n s , i n p a r t i c u l a r t h e C o l l i s i o n Deformation C l a s s i f i c a t i o n (CDC/VDI) ( 8 ) , s p e e d s , and o b j e c t s c o n t a c t e d. The n a r r a t i v e , c o l l i s i o n diagram, b l a c k and w h i t e p h o t o s , and 35mm s l i d e s a r e used i n t h i s r e v i e w. The Damage A n a l y s i s Sup- plement i s a l s o checked o v e r o r f i l l e d i n a t t h i s p o i n t. An occupant i n j u r y s p e c i a l i s t t h e n e d i t s t h e i n j u r y d e t a i l c o d i n g and completes a n Occupant Supplement w i t h Occupant I n j u r y C l a s s i f i c a t i o n ( O I C ) c o d i n g , i f none was s u p p l i e d. The e n t i r e e d i t e d c a s e and added c o d i n g a r e second e d i t e d by a second s t a f f p e r s o n t o e n s u r e o v e r a l l c o n s i s t e n c y and c o r r e c t n e s s. A f t e r keypunching and key v e r i f i c a t i o n , t h e c a r d s a r e r e a d i n t o H S R I ' s PDP 11/45 f o r c h e c k i n g , f o r m a t t i n g , and c u m u l a t i o n. Q u a r t e r l y , t h e compiled c a s e s a r e b u i l t i n t o t h e L e v e l - I 1 1 o r i n - d e p t h d a t a a n a l y s i s f i l e s ( S e c t i o n 3 ). The l a s t f i l e u p d a t e r p e r f o r m e d i n March, 1975, r e s u l t e d i n a d a t a b a s e of 7,799 c a s e v e h i c l e c l i n i c a l i n v e s t i g a t i o n s. Of t h e s e , 3,290 were MDAI c a s e v e h i c l e s t h a t were d i s t r i b u t e d by team, a s d i s p l a y e d i n T a b l e 3. An a b b r e v i a t e d o r e x c e r p t e d codebook of 40 key summary v a r i a b l e s f o r t h e 3,290 MDAI c a s e s ( i n c l u d i n g 1973 and 1974 Calspan Level-I11 c a s e s ) i s p r o v i d e d i n Appendix C. Over t h e twelve-month c o n t r a c t p e r i o d H S R I h a s e d i t e d and p r o c e s s e d 3,598 C P I R forms i n t o computer s t o r a g e , i n c l u d i n g 1 , 9 9 3 C P I R forms p r e p a r e d by MDAI teams ( F i g u r e s 1 and 2 ). The backlog of MDAI c a s e s was completed d u r i n g t h e f i r s t s i x months o f t h e c o n t r a c t by p r o c e s s i n g an a v e r a g e of 190 MDAI c a s e ve- h i c l e s p e r month. G e n e r a l l y , new c a s e s a r e r e t u r n e d t o NHTSA
w i t h i n 30 days of r e c e i p t by HSRI. During^ t h a t^ p e r i o d ,^ new c a s e s a r e logged, e d i t e d , keypunched, and passed t h r o u g h t h e i n i t i a l computer e d i t c h e c k s.
Processed MDAI Case V e h i c l e s , by Team
AA - Ann Arbor, HSRI 206
BC - Boston U n i v e r s i t y 142
G I - Georgia I n s t i t u t e of Technology 102 I U - I n d i a n a U n i v e r s i t y
ML - Maryland Medical/Legal Foundation NM - U n i v e r s i t y of New Mexico OS - Ohio S t a t e U n i v e r s i t y RT - Research T r i a n g l e I n s t i t u t e 108 RU - U n i v e r s i t y of R o c h e s t e r SC - U n i v e r s i t y of S o u t h e r n C a l i f o r n i a S I - S t a n f o r d Research I n s t i t u t e ( 2 ) SR - S t a n f o r d Research I n s t i t u t e (1) SU - S t a n f o r d U n i v e r s i t y SW - Southwest Research I n s t i t u t e 321 TR - Trauma Research Group, UCLA 69 TU - Tulane U n i v e r s i t y 64 UK - U n i v e r s i t y of Kentucky 64 UO - U n i v e r s i t y of Oklahoma 90 UU - U n i v e r s i t y of Utah ' 272 TOTAL 3,
2.2 QUALITY CONTROL AND DOCUMENTATION Q u a l i t y c o n t r o l i s one of t h e c r i t i c a l e l e m e n t s of t h e MDAI d a t a management program. The computer forms become t h e
primary s u r r o g a t e f o r each MDAI c a s e. While d a t a f i l e e r r o r s can be c o r r e c t e d , they must f i r s t be d e t e c t e d. For example, once a Volkswagen i s i n c o r r e c t l y coded a s an Opel, it may b e permanently l o s t t o anyone s u b s e q u e n t l y conducting a s t u d y of Volkswagens. S u p e r i o r f i e l d i n v e s t i g a t i v e e f f o r t s can be s e r i o u s l y damaged o r d e t e r i o r a t e d by a few coding e r r o r s. While it may b e b e t t e r t o p r o c e s s t e n c a s e s c o r r e c t l y r a t h e r t h a n a hundred of q u e s t i o n a b l e q u a l i t y , t h e b a s i c o b j e c t i v e
employing procedures t h a t minimize coding e r r o r s and d e t e c t t h o s e t h a t a r e made. Thus s e v e r a l q u a l i t y c o n t r o l s t e p s a r e followed i n an a t t e m p t t o e n s u r e t h e q u a l i t y of t h e r e s u l t i n g automated d a t a b a s e. These s t e p s were i n s t i t u t e d t o p r o v i d e a s u f f i c i e n t number of checks on t h e coding and checks on t h e checks. S p e c i f i c a l l y t h e f o l l o w i n g s t e p s were performed w i t h t h e guidance and approval of t h e NHTSA c o n t r a c t t e c h n i c a l manager: A l l of t h e 1973 e d i t i n g c r i t e r i a , c o r r e c t i o n s , and i n t e r - p r e t a t i o n s of q u e s t i o n s were expanded and improved. The r e s u l t i n g e d i t i n g manual i n c r e a s e s i n t e r - e d i t o r c o n s i s - t e n c y and h a s a i d e d i n t h e t r a i n i n g of new e d i t o r s. The documentation provided i n t h e MDAI d a t a automation program h a s a l s o been widely u t i l i z e d by t h e MDAI f i e l d teams. Comments from each of t h e teams and by NHTSA s t a f f have been i n c o r p o r a t e d i n t h e 1975 MDAI- Report Automation E d i t i n s Manual and Reference Information ( 3 , 4 ). T h i s updated documentation should c o n t i n u e t o reduce t h e v a r i - ance w i t h which t h e f i e l d d a t a have been r e c o r d e d.
i n t h e o r i g i n a l p r e p a r a t i o n of d a t a forms by a s s i s t i n g experienced f i e l d i n v e s t i g a t o r s. T h i s f i e l d e x p e r i e n c e proved t o be p a r t i c u l a r l y v a l u a b l e and should b e empha- s i z e d i n any f u t u r e MDAI r e p o r t automation programs.
A l l keypunched d a t a were 100 p e r c e n t key v e r i f i e d. Also, any keypunch e r r o r s d i s c o v e r e d i n subsequent q u a l i t y con- t r o l s t e p s were checked a g a i n s t t h e s o u r c e document and arrangements were made f o r c o r r e c t i o n s by t h e keypunch s t a f f. A l l keypunching and v e r i f y i n g was performed by H S R I s t a f f , who have an a v e r a g e of f o u r y e a r s ' e x p e r i e n c e w i t h C P I R computer forms.
A package of p r e - b u i l d programs performs o v e r 400 checks f o r i n v a l i d codes and i n t e r n a l d a t a i n c o n s i s t e n c i e s such a s r e a r - d o o r damage on two-door c a r s. The program was documented i n t h e 1973 MDAI Report Automation Program Re- view ( 9 ) and i s executed on t h e I n s t i t u t e ' s PDP 11/ computer.
5. The p r e - b u i l d d a t a checking programs produce weekly e r r o r comment l i s t s t h a t a r e reviewed w i t h t h e o r i g i n a l coding and documentation. E i t h e r t h e keypunched c a r d s a r e c o r r e c t e d o r t h e d a t a a r e c o r r e c t e d i n subsequent f i l e p r o c e s s i n g s t e p s.
6. Four times a y e a r t h e c a s e s compiled by t h e p r e - b u i l d programs were used t o update t h e d a t a a n a l y s i s f i l e s a v a i l a b l e t o u s e r s. The new d a t a a r e f i l e b u i l t , and u n i - v a r i a t e o r one-way frequency d i s t r i b u t i o n s a r e computed f o r each numeric v a r i a b l e i n t h e new d a t a. T h i s p r i n t o u t
b e f o r e t h e new d a t a a r e added t o t h e e x i s t i n g d a t a b a s e. 7. Data c o r r e c t i o n s c o n t i n u e t o b e made t o t h e e x i s t i n g com- p u t e r d a t a b a s e , i n r e s p o n s e t o comments r e c e i v e d by a l l t h e d a t a a n a l y s t s and f i l e u s e r s. T h i s form of feedback
u s e r s and c o r r e c t i n g t h e d a t a f i l e. I n c o n t r a s t t o most