How to interpret and trade with LME inventory data

before the actual data is out, there is an forecast of what the inventory level might be. This forecast is done by analysts.

If the Actual data is ahead of the forecast or below it, then there is sharp movement in the commodity price. If the Actual data comes up close to the expected figure, the movement is very minimal.

there is a nice calendar at http://www.forexfactory.com/ with the forecast and impact level to each inventory data.

example :

Copper inventory forecast is -250; actual report comes as +125. Interpretation = there is more inventory than expected. "more stock than demand"...In this scenario, Copper price would react sharply on the downside.