calc_allrmds            Calculate restricted mean durations for each
                        health state and all three models
calc_haz_psm            Derive pre and post-progression hazards of
                        death under PSM
calc_likes              Calculate likelihoods for three three-state
                        model structures
calc_rmd                Calculate restricted mean durations
calc_surv_psmpps        Derive PPS survival function under a PSM
check_consistent_pfs    Check consistency of PFS definition Check that
                        PFS is defined consistently with TTP and OS in
                        a dataset. This convenience function compares
                        'pfs.durn' with the lower of 'ttp.durn' and
                        'os.durn', and checks that the event field
                        'pfs.flag' is consistent with 'ttp.flag' and
                        'os.flag' (is 1 when either 'ttp.flag' or
                        'os.flag' is one).
compare_psm_likes       Compare likelihoods of PSMs
constrain_survprob      Constrain survival probabilities according to
                        hazards in a lifetable Recalculated constrained
                        survival probabilities (by week) as the lower
                        of the original unadjusted survival probability
                        and the survival implied by the given lifetable
                        (assumed indexed as years).
create_dummydata        Create dummy dataset for illustration
create_extrafields      Create the additional time-to-event endpoints,
                        adjusting for cutpoint
find_bestfit            Find the "best" survival regression from a list
                        of model fits
fit_ends_mods_par       Fit multiple parametric survival regressions to
                        the multiple required endpoints
fit_ends_mods_spl       Fit multiple spline regressions to the multiple
                        required endpoints
graph_psm_hazards       Graph the PSM hazard functions
graph_psm_survs         Graph the PSM survival functions
graph_survs             Graph the observed and fitted state membership
                        probabilities
prob_os_psm             Calculate probability of being alive in a
                        partitioned survival model
prob_os_stm_cf          Calculate probability of being alive under the
                        state transition clock forward model
prob_os_stm_cr          Calculate probability of being alive under the
                        state transition clock reset model
prob_pd_psm             Calculate membership probability of progressed
                        disease state in a partitioned survival model
prob_pd_stm_cf          Calculate probability of having progressed
                        disease under the state transition clock
                        forward model
prob_pd_stm_cr          Calculate probability of having progressed
                        disease under the state transition clock reset
                        model
prob_pf_psm             Calculate probability of being progression free
                        in partitioned survival model
prob_pf_stm             Calculate probability of being progression free
                        in either state transition model (clock forward
                        or clock reset)
prob_pps_cf             Calculate probability of post progression
                        survival under the state transition clock
                        forward model
prob_pps_cr             Calculate probability of post progression
                        survival under the state transition clock reset
                        model
vlookup                 VLOOKUP function
