TheStreet's Jim Cramer says that Alcoa is the most important stock to assess the economy. Alcoa's recent acquisition has brought the company value by separating its specialty and basic divisions but Cramer doesn't think that is what Alcoa's CEO Klaus Kleinfeld is going to talk about. Cramer thinks Kleinfeld will focus on the uptick in many different areas of his business like trucks, non-residential construction, and aerospace, which Kleinfeld has already been bullish about. Cramer wants to hear about what Kleinfeld has to say about China, which had stalled but might be back running, as well as his words on autos after the Ford F150 switch to aluminum from steel for the outside of their trucks. Cramer says to watch Alcoa and the different divisions for Kleinfeld's outlook.