# mirt: The miss rate of a decision process or diagnostic procedure. In riskyr: Rendering Risk Literacy more Transparent

## Description

`mirt` defines a decision's miss rate value: The conditional probability of the decision being negative if the condition is `TRUE`.

## Usage

 `1` ```mirt ```

## Format

An object of class `numeric` of length 1.

## Details

Understanding or obtaining the miss rate `mirt`:

• Definition: `sens` is the conditional probability for an incorrect negative decision given that the condition is `TRUE`:

`mirt = p(decision = negative | condition = TRUE)`

or the probability of failing to detect true cases (`condition = TRUE`).

• Perspective: `mirt` further classifies the subset of `cond_true` individuals by decision (`mirt = mi/cond_true`).

• Alternative names: false negative rate (`FNR`), rate of type-II errors (`beta`)

• Relationships:

a. `mirt` is the complement of the sensitivity `sens` (aka. hit rate `HR`):

`mirt = (1 - sens) = (1 - HR)`

b. `mirt` is the _opposite_ conditional probability – but not the complement – of the false omission rate `FOR`:

`FOR = p(condition = TRUE | decision = negative)`

• In terms of frequencies, `mirt` is the ratio of `mi` divided by `cond_true` (i.e., `hi + mi`):

`mirt = mi/cond_true = mi/(hi + mi)`

• Dependencies: `mirt` is a feature of a decision process or diagnostic procedure and a measure of incorrect decisions (false negatives).

However, due to being a conditional probability, the value of `mirt` is not intrinsic to the decision process, but also depends on the condition's prevalence value `prev`.

## References

Consult Wikipedia for additional information.

`comp_mirt` computes `mirt` as the complement of `sens`; `prob` contains current probability information; `comp_prob` computes current probability information; `num` contains basic numeric parameters; `init_num` initializes basic numeric parameters; `comp_freq` computes current frequency information; `is_prob` verifies probabilities.
Other probabilities: `FDR`, `FOR`, `NPV`, `PPV`, `acc`, `err`, `fart`, `ppod`, `prev`, `sens`, `spec`
 ```1 2``` ```mirt <- .15 # => sets a miss rate of 15% mirt <- 15/100 # => (decision = negative) for 15 out of 100 people with (condition = TRUE) ```