When you select multiple columns for match analysis, the transformation calculates an average score for each record based on the scores in the columns. The average score includes any weight values that you apply to the comparison algorithms for each column.
By default, all algorithms use a weight value of 0.5. You can increase this value if the selected columns are more likely to contain duplicated information. You can decrease the weight value if duplicate values in the selected columns are less likely to indicate genuine duplicate information between records. The Match transformation uses the average score as the single match score for each pair of records.