You can define thresholds and penalties to control what memoQ should consider as a match or a good match in a translation memory. These are defined in percents (indicating the necessary match rate). You can control what match rate qualifies as a match (the default is 60%), and what match rate is needed for a good match (the default is 80%). You can also set penalties: for example, you can deduce a few percents from the match rate if the translation unit comes from alignment or a specific translator.
These rates comprise a type of light resource: