The formula used to determine a partial match between the two stacks depends on the average length of the stacks. If the average stack length is:
< 4 -- 100% (exact match)
4 -- at least 75% of the stack has to match
5 -7 -- at least 60% of the stack has to match
> 8 -- at least 40% of the stack has to match
However, this can be overidden by using the Fault_Analyzer_Match_Percentage .ini variable, which applies the specified percentage to the number of matching function names in the two stacks, regardless of average stack length.