Both drama's contain
+sweet romantic comedy
+period drama
+real voices
+fluffy drama with playful male lead
+investigate/crime
+death of a parent

+A group of youths in school.
+Male leads
+group of friends
+Talks about friendship
+idol related

Both the male and 2nd male lead are the same in both drama's and both are high school based.

Similar between both dramas
+smart male lead
+ sweet female lead
+ school related drama
+ not real sibling, youth

Both dramas has
+ Both drama has to do with car accident.
+ secret love
+Fake sibling
+both has Ryan Ren
+school romance, smart male lead
+bright female lead