Bah humbug! Association between sending Christmas cards to trial participants and trial retention : randomised study within a trial conducted simultaneously across eight host trials
Citation
Coleman , E , Arundel , C , Clark , L , Doherty , L , Gillies , K , Hewitt , C A , Innes , K , Parker , A , Torgerson , D & Treweek , S 2021 , ' Bah humbug! Association between sending Christmas cards to trial participants and trial retention : randomised study within a trial conducted simultaneously across eight host trials ' , BMJ , vol. 375 , e067742 . https://doi.org/10.1136/bmj-2021-067742
Rights
This is an Open Access article distributed in accordance with the terms of the Creative Commons Attribution (CC BY 4.0) license, which permits others to distribute, remix, adapt and build upon this work, for commercial use, provided the original work is properly cited. See: http://creativecommons.org/licenses/by/4.0/.