Complex sentence: The E-FIT and Pro-fit systems used in the UK have been subjected to a number of formal academic examinations, which typically show that both produce composites that are correctly named, either immediately or a few hours after construction, only about 20% of the time.
Split into simpler sentences: The E-FIT and Pro-fit systems used in the UK have been subjected to a number of formal academic examinations. In these studies, composites were correctly named, either immediately or a few hours after construction, approximately 20% of the time.