How Quickly Does National Product Adjust to Aggregate Demand?

Note: we have both underreaction and overreaction:

• Rising aggregate demand can call forth greater than one-for-one increases in national product as firms respond by thinking that it is time to rebuild their inventories back up to normal levels.
• Conversely, falling aggregate demand can call forth greater than one-for-one decreases in national product as firms respond by thinking that it is time to cut back on their inventories.
• This actually happened in the business cycle that started in 1990...