Table 2.

Time to death models (TTD) applied to the pooled CheckMate-017 and CheckMate-057 EQ-5D-3L data using the UK value set

Statistical model	All patientsa [n = 788, N = 4850]		Confirmed death only used in model fits i.e. excluding censors [n = 718, N = 3627]		Last year of life only used in model fits [n = 587, N = 2007]		Artificially censoring at 24 months follow-up [n = 617, N = 2645]
	MAE	QICu	MAE	QICu	MAE	QICu	MAE	QICu
$\mathit{TTD}$	0.184	4853	0.183	3629	0.193	2009	0.184	2656
$\mathrm{L}\mathbf{o}\mathbf{g}(\mathit{T}\mathit{T}\mathit{D})$	0.173	4847	0.178	3628	0.190	2008	0.179	2656
$1/\sqrt{\mathit{TTD}}$	0.179	4847	0.177	3628	0.190	2008	0.180	2656
${1/e}^{\mathit{TTD}}$	NA	NA	NA	NA	0.201	2009	0.193	2652
${\mathit{TTD}}^2$	NA	NA	NA	NA	0.195	2009	0.186	2656
${\mathit{TTD}}^2+TTD$	NA	NA	NA	NA	0.190	2010	0.181	2657
Time to death grouping (≤4 weeks, 5–26 weeks, 27–52 weeks, ≥52 weeks)	0.175	4849	0.178	3631	0.191	2011	0.180	2658
Progression-based utilities (pre/post progression)	0.193	4852	0.191	3629	0.201	2009	0.194	2656

Bold formatting shows the preferred Log(TTD) model fit

n number of patients, N number of observations, MAE mean absolute error, QICu Quasi Information Criterion, TTD time to death (days), NA not applicable (model did not converge)

^aDate last known alive used as the date of death for continuous TTD models