Generate a tidy table of incremental cost-effectiveness ratios (ICERs) given output from
`cea_pw()`

with `icer()`

and format for pretty printing with `format.icer()`

.

```
icer(x, prob = 0.95, k = 50000, labels = NULL, ...)
# S3 method for class 'icer'
format(
x,
digits_qalys = 2,
digits_costs = 0,
pivot_from = "strategy",
drop_grp = TRUE,
pretty_names = TRUE,
...
)
```

- x
An object of class

`cea_pw`

returned by`cea_pw()`

.- prob
A numeric scalar in the interval

`(0,1)`

giving the confidence interval. Default is 0.95 for a 95 percent interval.- k
Willingness to pay per quality-adjusted life-year.

- labels
A list of named vectors containing the values and labels of variables. The elements of each vector are the values of a variable and the names are the labels. The names of the list are the names of the variables. See the output returned by

`get_labels()`

for an example.- ...
Further arguments passed to and from methods. Currently unused.

- digits_qalys
Number of digits to use to report QALYs.

- digits_costs
Number of digits to use to report costs.

- pivot_from
Character vector denoting a column or columns used to "widen" the data. Should either be

`"strategy"`

,`"grp"`

,`"outcome"`

, or some combination of the three. There will be one column for each value of the variables in`pivot_from`

. Default is to widen so there is a column for each treatment strategy. Set to`NULL`

if you do not want to widen the table.- drop_grp
If

`TRUE`

, then the group column will be removed if there is only one subgroup; other it will be kept. If`FALSE`

, then the`grp`

column is never removed.- pretty_names
Logical. If

`TRUE`

, then the columns`strategy`

,`grp`

,`outcome`

, and`value`

are renamed (if they exist) to`Strategy`

,`Group`

,`Outcome`

, and`Value`

.

`icer()`

returns an object of class `icer`

that is a tidy
`data.table`

with the following columns:

- strategy
The treatment strategy.

- grp
The subgroup.

- outcome
The outcome metric.

- estimate
The point estimate computed as the average across the PSA samples.

- lower
The lower limit of the confidence interval.

- upper
The upper limit of the confidence interval.

`format.icer()`

formats the table according to the arguments passed.

Note that `icer()`

will report negative ICERs; however, `format()`

will
correctly note whether a treatment strategy is dominated by or dominates the
reference treatment.