added options to specify the cox-snell or nagelkerke’s r-squared
directly for binary outcome models
simplified continuous outcome models criteria 3 calculation fixing
MMOE=10% so that N=234+p
pmsampsize v1.1.2
(Release date: 2022-02-12)
fixes issue for continuous outcome models in criteria 4 in
calculating the CI for the intercept based on final SS
edit to criteria 2 for continuous outcomes to round up N
pmsampsize v1.1.1
(Release date: 2021-11-21)
fixes issues with rounding leading to small differences in Max_Rsq
and subsequently sample size calculations
additional output including Nagelkerke’s R-sq (binary & survival
outcomes)
pmsampsize v1.1.0
(Release date: 2021-06-24)
update allowing user to input C-statistic from existing model to
approximate Cox-Snell R-squared (for binary outcome model sample size
calculations)
additional parameter checks
pmsampsize v1.0.4
(Release date: 2020-07-24)
version issues fixes
pmsampsize v1.0.3
(Release date: 2020-07-23)
Continuous outcomes:
calculation of shrinkage for each criteria based on N needed in
specific criteria
also allowance for the unique scenario when starting N already
meets shrinkage requirement set by user (this is more for academic
exercise, as in practice a high shrinkage will be desired and so it is
very rare that the base N (set to p+2) will provide good
shrinkage)
Binary and TTE outcomes:
more informative error message added for rare scenario where
shrinkage is specified lower than r-squared which results in NaNs from
shrinkage formula
pmsampsize v1.0.2
(Release date: 2019-11-15)
update forces the time-unit to be the mean follow-up time, as
described in forthcoming BMJ paper which extends the original Statistics
in Medicine paper (see reference in help file)
updated in calculation of max R-sq for survival option, to
prevent manipulation based on time units used
pmsampsize v1.0.1
(Release date: 2019-08-02)
updated in line with correction to original article in eq. 13