Cross Section Rating Fields

Rating InputsRating Outputs
Number of miles/sites. Depending on the treatment being evaluated, this may include sites with and without the treatment. In other cases, the range of each independent variable of interest should be adequate (for analysis based on "segments", number of miles should be used; for analysis based on intersections or similar units, sites should be used 100+ Rating for number of miles/sites. 20
Exact number of miles/sites if known.    
Number of crashes for all sites combined. 500-699 Rating for number of crashes for all sites combined. 15
Actual number of crashes for all sites combined if known.    
At least two years with actual/estimated traffic volume counts in the study period. yes Rating for traffic volume counts in study period. 10
Selection bias (similarity of sites with and without the treatment). very Rating for selection bias. 25
Appropriate model form (including error terms). yes Rating for appropriate model form. 10
Appropriate functional form (including possibility of non-traditional non-GLM forms) yes Rating for appropriate functional form. 10
Appropriate consideration of omitted variable bias (i.e., variables known to influence safety were considered as terms in the model or controlled through study design). yes Rating for appropriate consideration of omitted variable bias. 10
Appropriate consideration of correlation between independent variables (with significant correlation, the coefficient of variables may have the wrong sign). yes Rating for appropriate consideration of correlation between independent variabes. 10
Appropriate consideration of spatial and temporal correlation. yes Rating for appropriate consideration of spatial and temporal correlation. 10
CMF is statistically significant at 0.05, 0.10, or 0.15 levels. 0.05 Rating for CMF significance level. 20
    RATING TOTAL 140

Read more about how the Star Quality Rating scores are determined.