TY  - JOUR
AU  - Holland-Letz, Tim
AU  - Kopp-Schneider, Annette
TI  - Drawing statistical conclusions from experiments with multiple quantitative measurements per subject.
JO  - Radiotherapy and oncology
VL  - 152
SN  - 0167-8140
CY  - Amsterdam [u.a.]
PB  - Elsevier Science
M1  - DKFZ-2020-01724
SP  - 30-33
PY  - 2020
N1  - 2020 Aug 20;152:30-33#EA:C060#LA:C060#
AB  - In experiments with multiple quantitative measurements per subject, for example measurements on multiple lesions per patient, the additional measurements on the same patient provide limited additional information. Treating these measurements as independent observations will produce biased estimators for standard deviations and confidence intervals, and increases the risk of false positives in statistical tests. The problem can be remedied in a simple way by first taking the average of all observations of each specific patient, and then doing all further calculations only on the list of these patient means. A more sophisticated statistical modeling of the experiment, for example in a linear mixed model, is only required if i) there is a large imbalance in the number of observations per patient or ii) there is a specific interest in actually identifying the various sources of variation in the experiment.
LB  - PUB:(DE-HGF)16
C6  - pmid:32828840
DO  - DOI:10.1016/j.radonc.2020.08.009
UR  - https://inrepo02.dkfz.de/record/157627
ER  -