Not all sections in the Network Master have equal importance in the analysis. For example, bridges with bigger deck areas are typically more important in decision-making and can therefore be assigned a higher index weight. Index weight is designed to include the relative importance of structures in the model. The index weight calculation formula can be set either in the Calculated Expressions screen or by a groovy script. In the analysis, if no groovy script is provided, then the Calculated Expression (using SQL script) is used.