input: Check inventory Forecasts will help you confirm whether ad impressions are available before you book inventory in a line item. If the forecast confirms that ad inventory is available, you can move the forecast data into a line item in a new order or an existing order. With forecasts, you can optimize your ad inventory and prevent overbooking or underselling. For more information on differences between forecasting in DART for Publishers and DoubleClick for Publishers, see Check available inventory. [Term in DART for Publishers] 
output: Availability forecast The DART forecasting tool that is used to predict the availability of inventory. Availability Forecast is used in two ways: During the sales process, to estimate how much inventory is available for sale When an ad is booked If there is not enough inventory predicted to meet the requirements of the ad, the Availability Forecast report is automatically displayed to inform the trafficker of the problem.