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# Deficit Parameter
## General Description
Parameter track the deficit (max\_flow - actual flow) of a Node. [API Reference](https://pywr.github.io/pywr-docs/master/api/generated/pywr.parameters.DeficitParameter.html)
Notes: This parameter is a little unusual in that it’s value is calculated during the after method, not calc\_values. It is intended to be used in combination with a recorder (e.g. NumpyArrayNodeRecorder) to record the deficit ( defined as requested - actual flow) at a node. Note that this means recording this parameter does *not* give you the value that was used by the solver in this timestep. Alternatively, this parameter can be used in the model by other parameters and will evaluate to *yesterdays* deficit, where the deficit in the zeroth timestep is zero.
## Attributes
Name
Description
Required
model
pywr.model.Model
Yes
node
The node that will have it’s deficit tracked
Yes
## Example
coming soon...
```json
{
}
```
---
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