Formula (Extended): $ISERROR Function
## Overview
Return true if the argument is an error.
## Syntax
```
$ISERROR(Value)
```
## Parameters
|Parameter|Type|Required|Description|
|:---|:---|:---|:---|
|Value|Formula|Required|Value, formula, or formula to check for error|
### Column Usable as Parameters
|Parameter|Classification|Numerical Value|Date|Description|Check|
|:---|:---|:---|:---|:---|:---|
|Value|Yes|Yes|Yes|Yes|Yes|
## Return Value
True if an error occurs. False, Otherwise.
### Return Value for Target Column
|Target|Return Value|
|:---|:---|
|Classification (including title, status, manager, owner)|Display the string "True" or "False"|
|Numerical Value (including work volume, progression rate, remaining work volume)|Do not display|
|Date (including start and completion)|Do not display|
|Description (including content)|Display the string "True" or "False"|
|Check (including lock)|Check ON if true, check OFF if false|
## Usage Example ①
Specify parameters by screen column name (name displayed)
### Formula
![image](https://pleasanter.org/binaries/d7c4cf2e7f26439b903a98ba9b1c06ec)
### Parameters
![image](https://pleasanter.org/binaries/cb4c4c9047bb41c18f7f93a89ca4da45)
### Calculation Result
![image](https://pleasanter.org/binaries/68e174170cf7409493fc33bbff2574b1)