Assertion: tapeworm's part | /r/HasProperty | difficulty
Facets:
value: in finding known negatives
type: OTHER
value: for tapeworm infection
type: PURPOSE
Source sentences:
text: The hard part in developing an accurate diagnostic test is difficulty in finding known negatives and known positives (horses that have definitive diagnoses–negative or positive–for tapeworm infection) to check the validity of the test.