Summarize costs and quality-adjusted life-years (QALYs) given output simulated
from an economic model. The summary output is used to perform
cost-effectiveness analysis with `cea()`

and `cea_pw()`

.

`summarize_ce(costs, qalys, by_grp = FALSE)`

## Arguments

- costs
Simulated costs by category (objects of class `costs`

).

- qalys
Simulated QALYs (objects of class `qalys`

).

- by_grp
If `TRUE`

, then costs and QALYs are computed by subgroup. If
`FALSE`

, then costs and QALYs are aggregated across all patients (and subgroups).

## Value

An object of class `ce`

.

## Details

If mean costs and/or QALYs have already been computed
(i.e., an average within a population), then there
must be one observation for each discount rate (`dr`

),
PSA sample (`sample`

), treatment strategy (`strategy_id`

),
and health state (`state_id`

). Alternatively, there can be a column
denoting a patient (`patient_id`

), in which case outcomes will first be
averaged across patients. A `grp_id`

column can also be used so that
outcomes are computed for each subgroup (if `by_grp = TRUE`

); otherwise it is assumed that
there is only one subgroup.