The Confusion Between Christie's Plays and Her Own Works

A number of the third party adaptations that carry her name are markedly inferior to her own work. The proper distinction is made between her own plays and those written by others who borrowed her name which plays written or co-written kind of sorta by other people do you think are the worst culprits here? Agatha Christie's reputation as a playwright has been developed through otherplaywrights including Maastra, Merritt the Vicridge and Perla Endhouse on Ridley again  on eve of World War II.