BIAS IN THE TAD SEVERITY SCALE

THE TAD VEHICLE DAMAGE SCALE WAS DESIGNED TO REFLECT BOTH THE POINT OF IMPACT AND DAMAGE SEVERITY. POINT OF IMPACT IS DESIGNATED BY ALPHA CODES AND DAMAGE SEVERITY IS INDICATED BY NUMERICAL CODES. THE SEVERITY SCALE IS A SEVEN-POINT SCALE WITH THREE "ANCHOR" POINTS, REPRESENTED BY PHOTOGRAPHS AT LEVELS 2, 4 AND 6. BECAUSE ALL TAD SEVERITY LEVELS ARE NOT ANCHORED, THE QUESTION WAS ASKED: IS THE TAD SCALE BIASED DUE TO THE FACT THAT PHOTOGRAPHS ARE NOT PROVIDED FOR LEVELS 1, 3, 5, AND 7? THREE EXPERIMENTS WERE CONDUCTED IN AN ATTEMPT TO ANSWER THIS QUESTION. THE EXPERIMENTS CONSISTED OF HAVING SOME GROUPS OF SUBJECTS JUDGE THE DEGREE OF DAMAGE SUSTAINED BY CRUSHED BEER CANS, AND OTHER GROUPS OF SUBJECTS JUDGE THE DEGREE OF DENSITY OF RANDOM PATTERNS OF X'S ON THE BASIS OF SEVEN-POINT SCALES EMPLOYING THREE OR SEVEN PHOTOGRAPHIC LEVELS. COMPARISONS WERE THEN MADE TO DETERMINE THE DIFFERENCES IN JUDGMENTS. THE RESULTS INDICATED THAT THE SUBJECTS USING THE SCALE WITH SEVEN PHOTOGRAPHIC LEVELS WERE: (1) LESS LIKELY TO OVERUSE ODD OR EVEN CATEGORIES, (2) LESS VARIABLE IN THEIR ESTIMATES, (3) MORE LIKELY TO RECORD DAMAGE AS LESS SEVERE, AND (4) MORE ACCURATE. /AUTHOR/

• Corporate Authors:

  University of North Carolina, Chapel Hill

  Highway Safety Research Center
  Chapel Hill, NC  United States  27599
• Authors:
  • Griffin, L I
• Publication Date: 1973-7

Media Info

• Features: Figures; References; Tables;
• Pagination: 47 p.

Subject/Index Terms

• TRT Terms: Accuracy; Injury severity; Loss and damage; Silts; Traffic crashes; Weighing devices
• Uncontrolled Terms: Scale; Severity
• Subject Areas: Highways; Safety and Human Factors;

Filing Info

• Accession Number: 00224518
• Record Type: Publication
• Files: TRIS
• Created Date: May 15 1974 12:00AM