If it's released. Those guys have plenty of songs that are average. I've heard them. Also, some released flops. Britney's "Ooh La La" which just came out, and some stuff on the Emblem 3 album.
individually they have their misses for sure, but when kotecha/shellback/martin are all together and the track is released as a single, I don't think it's ever not been a hit. "scream", "one more night", "loser like me", "i wanna go", "dj got us falling in love", etc. that britney song did do pretty shitty but only dr. luke was involved with that. he didn't work on the cassadee album