The Structured Query request accepts a weighted metadata expression that acts like a preference for the retrieved index items. The standard query request uses this preference to impact the final relevance of the matching statements; the structured query request uses it to impact the final relevance of the aggregated results, using the following attribute:
<structquery weightContrib="wgt
"
The wgt value can be any number from 0 to 100, and defaults to 0. This value represents the percentage of the final relevance comes from the compute value of the weighted expression.